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C.E., F.R.S.E. - • By permission of the Council. Excerpt Minutes of Proceedings of The Institution of Civil Engineers, Vol. xl. Session 1874-75. — Part ii. Edited by James Forrest, Secretary. LONDON : PRINTED BY WILLIAM CLOWES AND SONS, STAMFORD STREET AND CHARING CROSS. 1875. [^The right of rublication and of Tramlation U rtterved.] ,-j. ..; ;,. ;■ 'i ADVERTISEMENT. y ' I The Institution is not, as a body, responsible for the facts and opinions advanced in the following pages. b b THE INSTITUTION OF CIVIL ENGINEERS. Sect. II.— OTHER SELECTED PAPEES. No. 1,413. — " Notes on Public Works in the United States and in Canada, including a description of tlie St. La-wrence and the Mississippi Rivers and their main Tributaries." By Sir Chables A. Hartley, M. Inst. C.E., F.R.S.E. Having visited the United States and Canada in the autumn of 1873, the accompanying notes on certain engineering works of mag- nitude are submitted, in the hope that they may prove interesting to the members. I,— EAILROADS AND BRIDGES. Philadelphia and Reading Railroad.^ (Visited ISth November, 1873.) — Through the kindness of Mr. Gowen, the President of this Company, and Mr. NicoUs, the second Vice-President, the Author had an opportunity of visiting the principal -works on this railroad, which, in point of finish and substantial work, is equal to any line that he has travelled on in Europe. Mr. Nicolls has kindly enabled the Author to correct his notes up to the 31st of November, 1874. The total length of single and double tracks and sidings is 1,452 miles, thus distributed : — Single Track. Double Track. Length Sidings Total Length of Tracks and Sidings. of ^^- LatTr^ls. 1 Eoads owned . . Boads leased . . Roads contracted Aggregate . . Miles. 171-9 279-4 42-9 Miles. 155-1 76-0 Miles. 327-0 355-4 42-9 Miles. 283-6 196-5 15-3 Wiles. 765-7 627-9 58-2 494-2 231-1 725-3 495-4 1,451-8 ' For complete statistical iuformation respecting the railways of America re- ference may be made to the " Manual of the Railroads of the United States,"' by Henry V. Poor, and to the " American Raibroad Manual," by Edward Vernon, both of which are published annually in New York, B 2 4 OTHER SELECTED PAPERS. The workshops and rolling mills of tho Company aro at Eeading. a flourishing town of forty tliousand inhabitants, 58 miles from Philadelphia. Both locomotive and marine engines are fitted up at these shops, where tho cranes aro all worked by hydraulic power. The mills are connected with four puddling and ten heating furnaces, and the hot blast evolved from the furnaces is employed as at Phoenixville. In 1874; 20,000 tons of iron rails were rolled, the rails being 24 feet long and weighing 08 lbs. per yard. The two holes for tho fish-plates at each end of the rails were punched cold simultaneously. Steel rails of the same pattern as the 08-lbs. iron rails weigh 70 lbs. per yard. Up to the 30th of November, 1874, 1,588 tons of steel rails had been rolled in tho Company's rolling mill, and an aggregate length of 92 miles had been laicl with these rails, with the best results, in the most exposed places on the line.^ The Company possess and work four hundred and five loco- motive engines. These cost K45G,245 for repairs in 1874. The traffic of the railroad principally consists of anthracite and bituminous coal, iron ore, lime and limestone, grain, petroleum, pig iron, lumber, and manufactures of ail kinds. The aggregate amount of traffic transported over the railroads of the Company in 1874 was as follows : — . , , iTumber of passengers carried 6,964,869 „ tons of coal, of 2,240 lbs 6,348,812 „ „ merchandise, of 2,000 lbs 3,098,831 „ „ Company's materials 493,591 Total tonnage of the Company in tons of 2,000 lbs., includ-'k ing weight of passengers and Company's materials . . / ' ' The Company's line penetrates into the heart of the anthracite basin of Pennsylvania ; but owing to the difficulties of the country, the coal is hauled up steep inclines by stationary engines. From C"ie coal field, the anthracite is sent to market by three separate ' According to the last report of the American Iron and Steel Association, the iron trade in the United States was more depressed at tjie close of 1874 than at any time since the panic began in September 1873. Pig iron, which in April 1873 had been sold at $42 to $47, had declined to $23 and $25 per ton ; bar iron, then 4 J cents per lb. at Pittsburg, had fallen to 2 J cents ; iron rails, quoted at $82 in 1873, could be bought for $48 per ton in New York or in Philadelphia. Only 1,900,000 tons of pig iron were produced in 1874 — a falling-off of one-third from the production of 1873. The manufacture of Bessemer steel rails was about the same in 1874 as in 1873 — 130,000 tons. The total manufacture of rails of all kinds was 450,000 tons, while 100,000 tons were imported. In 1872 there were 1,000,00^* tone made, besides a large importation. PHILADELPHIA AND READING RAILIIOAD. routes ; on two of which are three inclined phines of 2,410 feet, 4,650 feet, and 4,755 feet respectively, overcoming elevations of 354 feet, 318 feet, and 404 feet ; and by a tunnel 3,400 feet long, through a mountain forming the southern boundary of the coal field. On all these planes the rope is 2^ inches diameter ; on the first and steepest of steel, on the two last named of iron. On the first plane the cost of hatiling the coal in 1874 was 2yVV cents (l^d.) per ton of 2,240 lbs., including all expenses of fuel, wages, repairs, &c. The Philadelphia and Reading Coal and Iron Company owns one-third of the anthracite coal basin of Pennsylvania.* The running cost of trains hauling coal in 1874, per round trip of 190 miles from the coal region to tidewater and back with empty cars, transporting average loads of 647 tons, and average through loads of 522 tons of coal of 2,240 lbs. each, was 30.^ cents per ton carried through 95 miles, or at the rate of ^ of a cent (-^ of a penny) per ton per mile. The total cost of trains moving coal, including cost of roadway, superintendence, telegraph, police, and all expenses of working the road, proportional to coal, was f of a cent (| of a penny) per ton per mile. The Reading Railroad Company owns a fleet of fourteen iron steamers, equipped with the best known means of unloading cargo, weighing anchor, &c. The largest are of 540 HP., carrying 1,700 tons (of 2,240 lbs.) of coal on a draught of 15 feet, and make nearly 9 knots per hour so loaded. They are used for carrying coal from the Richmond terminus of the railway on tidewater in the Delaware river (where the Company's wharves have a frontage of Ih mile) to New York, Boston, Portland, Washington, and other ports accessible by sea. The Schuylkill canal now belongs to this Company. It is worked in conjunction with the railroad. The hamlet of Schuylkill Haven is at the head of the canalised river of Schuylkill, which communicates with the Delaware at Philadelphia. The Susque- hanna canal is also worked by the Company. The gross receipts of the railway for the year ending the 30th of November, 1874, were ^14,452,121 ; the expenses, ^8,731,916; and ' The produce from the eastern extremity of the great Schuylkill anthracite basin — which has its outlet at Mauch Chunk (Blue Mountain), said to be the most picturesque town in America — is conveyed to tidewater along the Lehigh and Susquehanna railway division of the Central railroad of New Jersey. In 1870 the quantity of coal sent eastward from Mauch Chunk averaged 200,000 tons per week. The total production of the anthracite basin of Peimsylvania was 19,585,178 tons in 1873, and 18,700,000 tons (estimated) in 1874. \ i 6 OTHER SELECTED PAPERS. the net profits, H5,720,205. The expenses, including renewal fund, rents of lateral roads, taxes, &c., were thus 60 j^ per cent, of the gross receipts. The not loss in 1874 in the business of the canals and of the steam colliers and barges was ^420,059. The following balance sheet — abridged from a statement in the last Koport of the President and managers of the Railway Company — shows the re- sources and financial condition of the Company on the 30th of November, 1874: — Dr. BailrnadB and Icpots Locomotives and cars . Beal estate .... Steam colliers Schuylkill canal and ] barges J Ship-yard at Port Rich-1 moud J Philadelphia & Reading Coal and Iron Co.'s bond and mortgage . Ditto stock . . . Railroad and telegraph^ stock J Assets in cash — Stocks and bonds, ma- terials, &c., less lia- bilities 2!), (330, 192 8,787,571 7,459,868 2,542,149 1,607,439 308,977 50,336,196 30,000,000 1,000,000 1,405,902 82,742,098 12,173,168 94,915,266 Or. Stock, $32,722,775 . Preferred stock,] $1,551,800 . . . Mortgages and deben- tures at from 5 to 7 1 per cent. . Loan of Schuy'kill Na-j vigation Co. . . . / Loan of East Pennsyl-I vania Railroad Co. . j Sinking Fund Bonds Reserved Fund, less Di-"t vidond Fund . . ./ 34,274,575 55,080,988 2,578,250 495,900 614,800 1,870,753 94,915,266 The Company has paid 10 per cent, dividend on its stock for some years past. Phcenixville Bridge Works, belonging to Clarke, Eeeves and Company. (Visited 26th November, 1873.) — These works are situated between Philadelphia and Eeading. The Author was accompanied by Mr. S. Reeves, the President of the Company, who supplied the principal part of the following information. From 1869 to 1873 the Company built seventy bridges, having an aggregate length of 35,000 feet, or 6^ miles of single track, comprising in all one hundred and seventy-six spans. With the present facilities they can turn out 100 feet of finished bridge for each working day in the year. Everything is done on the premises; beginning with the BRIDGE WORKS IN THE UNITED STATES. / manufacture of the iron from the ore ; next rolling it into the shapes required ; and, finally, applying the machine labour which completes the structure ready for erection. About fifteen hundred men are employed on the works. Two 300-HP. engines drive the blasts for the furnaces day and night, the air being heated by the consumption of the gases evolved. The Phoenix columns or tubes are made of from four to eight sections, rolled in the usual way up to 24 feet in length, and riveted together at the flanges. When necessary, they are joined together by cast-iron joint blocks with circular tenons, which fit into the hollows of each tube. The ends of all the links, to resist tensile strains, undergo a procp"" called die-forging, by which the head is shaped and the hole struck by hydraulic pressure at one operation. The threads of the screws are so formed that rupture, when under pressure, always occurs in the unscrewed part of the bar. The iron is required to be of such elasticity that, after being subjected to a tensile strain of 30,000 lbs. per square inch, it will return to the original dimensions ; while it should be so tough that bars, 2 inches in diameter, bent back from 90° to 180\ when cold, should show no sign of fracture. Mr. Keoves particularly directed attention to the fact that, as a rule, iron trussed bridges in America have all their principal parts formed by machinery. They are of imiform dimensions in similar spans, and hence are perfectly interchangeable. Thus machinery can be applied in their manufacture, and the cost at the works be reduced to a minimum. They are sj made, in fact, that nearly all the work is done at the shops, and they can be erected with the least possible amount of unskilled labour. • ' ,'. Keystone Buidge Company, Pittsburg. (Visited 15th November, 1873.) — Through the kindness of Messrs. McCandlish and Carnegie, the Author was shown over these works by Mr. Nicholls, the second engineer of the Company. The Company has built numerous bridges throughout the United States. Of these, the Author has seen the Steubenville bridge, which has three spans of 210 feet, four of 255 feet, and one channel span of 320 feet; the Newport and Cincinnati bridge, which has fourteen spans of 150 feet and one channel span of 420 feet ; and the Keokuk and Hamilton bridge, which has ten spans of 180. feet and one channel span of 387 feet. The Company has a capital of Kl, 500,000, and can turnout more than ^3,000,000 worth of work annually. It gives employment to six hundred and fifty men. Its business is to construct general 8 OTHER SELECTED PAPERS. machine work, and the substructuro and suporstrticturo of build- ings, bridges, &c,, in any part of the United States and Canada. Special pride is taken in obtaining lightness, strength, and economy, by employing wrought iron in tubular forms for com- pressiye strains, and weldless links in tension members. The esta- blishment is now almost exclusively occupied in completing the chrome-steel tubes for the great St. Louis bridge.^ The ultimate tensile strength of this steel is 100,000 lbs. per square inch; but the Author saw one 1-inch bolt which only yielded to 120,000 lbs. The ironwork for the bridge is required to bear an ultimate tensile strain of 60,000 lbs. per square inch. The steel staves com- posing the tubes are submitted to a tensile strain of 40,000 lbs., and to a compressive strain of 60,000 lbs., without permanent set. The ^-inch plate-steel for enveloping the staves is tested to 40,000 lbs. for compression and tension. There are six staves in each cylinder, and, after five have been placed, the sixth is driven home by a force of 20 tons. Railroad Bridgk across the Mississirri at Eock Island. (Visited Ist November, 1873.) — This bridge, which has often been termed, and apparently with justice, " the strongest and most perfectly finished bridge in America," was opened in the summer of 1872. The superstructure was designed by Mr. C. Shalor Smith, the President of the Baltimore Bridge Company, to whom the contract for the ironwork was awarded, in September 1870, for the sum of ^459,784. The workmanship, which was ;3uperintended by Major Benyaurd, under the direction of Colonel Macomb of the U.S. Corps of Engineers, is admirable in every particular. The abutments and piers, the construction of which had been in the charge of Major Sticknoy, were founded on the rock by means of ordinary coffeidams, at a depth which d'A not exceed 20 feet below low water. The masonry is uncommonly well built. There are two spai^s of 260 feet, three of 220 feet, one draw- bridge 368 feet long, covering two openings of 160 feet each, and two land spans of 196 feet and 100 feet. The total length is there- fore 1,844 feet. The trusses of the main bridge are ' double-system Whipple,'^ ' Chrome steel can be welded as well as the best wrought iron. The quantity of chromium required in the steel is so small that the cost of the alloy is not greater than that of carbon steel. In a pure and orystallised state it is a grey, very hard metal, not oxidizable by any acid, nor reducible in a furnace. '•' The late Mr. Zernh Colburn's Paper on " American Iron Bridges," in the Minutes of Proceedings Inst. C.E., vol. xxii., p. .540, will he found to contain an account of the best known systems. BRIDGE WORKS IN THE UNITED STATES. 9 in which everything but the washers, &c,, is of wrought iron. They are 33 feet high and 19 feet apart. T1\ero are two floors; the upper, for a single rail track, placed a little below the centre of the trusses, and the lower, for horses and carriages, on the bottom chords. The footpaths are on each side of the lower plat- form. The draw-span has a weight of 683 tons, of which four-fifths are placed on the thirty -six bearing wheels of the cast-iron turntable, 30 feet in diameter, and one-fifth on the centre pin. The swing is turned by hydraulic power in two and a half minutes, when there is no wind. It is opened about twelve times a day for the passage of vessels. The total weight of the superstructure of the bridge is 2,080 tons, distributed thus: 1,910 tons, ironwork; 90 tons, turntable; 90 tons, tramway and spikes ; and 890 tons, oak and pine lumber. The total cost of the bridge was K 1,000,000 (£200,000).' The diflferenco between ordinary high and low water at the lower end of Rock Island, whence the bridge crosses the main branch of the river to the city of IJavenport, is 16 feet, except when the ice packs momentarily and dams the water back to a height some- times of 24 feet above low water. Iron Trussed Railroad Bridge over the River Ohio at Cin- cinnati. (Visited 12th November, 1873.) — This bridge carries a single ' track ' and two wide footpaths over twenty -five ' deck ' or undergrade openings, varying from 60 feet to 245 feet, and two overgrade openings, one of 370 feet and the other of 400 feet. On the left or Kentucky bank a drawbridge, worked by two men, gives the river and canal craft two openings of 125 feet each, when they cannot pass freely under the overgrade openings. The ' draws ' are spanned by the ' Warren ' truss, the two mid- channel spaces by ' Fink ' triangular trusses, and all the others by ' Fink ' trussed girders. The line of roadway bearers of the Indiana Channel span is 96^ feet above low water and 45^ feet above highest water, the maximum oscillation being 51 feet. The total cost of the bridge from abutment to abutment was K 1,6 15, 200 (£323,000, or £61 per lineal foot for 6,294 feet). The piers and abutments are all founded on rock, which is almost bare at extreme low water. The contract price for the masonry was Kl5 (£3) per cubic yard, but much of it cost from K18 to K20, although tlio limestone of which the masonry is composed came from quarries in the immediate neighbourhood. The bridge is level for In these notes the dollar is assumed to be worth four sliilliuga. 10 OTHER SELECTED PAPERS. !;ii ii;> 2,242 feet, with a fall at each end of 79 feet per mile (1 in (37). Pilot engines assist heavy trains over these approaches. The speed over the bridge is restricted to 12 miles per hour nominally ; but the Superintendent said that a speed of 30 miles per hour is often run by risiiy drivers. The engines on which the Author traversed the bridge weighed 56 tons. Four of them at rest, weighing 200 tons and covering as many feet, only gave a deflection of 1|^ inch on the 400-feet span. The deflection, with the same load, on one of the 245-feet undergrade spans was 1^ inch. The weight of the 400-feet span complete, with stringers, cross-ties, track, foot- walk, railings, and pier bearings, is 4,162 lbs. (say 1^ ton) per lineal foot. All the wrought iron has been tested to a strain of 20,000 lbs. per square inch, and its breaking or ultimate strength has been proved at 60,000 lbs. per square inch. The maximum strain in practice with a full load is 12,000 lbs. per square inch, and 7,000 lbs. is the minimum strain. The Chief Engineer and de- signer of this, in every respect, first-class bridge was Col. Albert Fink. St. Charles Eailroad Biudge across the Missoqei at 20 miles FROM St. Louis. (Visited 10th November, 1873.) — This bridge, which is remarkable on account of the difficulty of its fourdations, was designed and constructed by Mr. C. Shalor Smith. It has seven spans ; four ' trellis ' or • double triangular girder truss,' of 320 feet each, and three Fink 'deck' trusses of 305 feet each. The rails are 90 feet above low water, or 51 feet above the extra- ordinary high- water mark of 1844. The track is single, without footways, and there are no ' draws.' There are eight river piers, and the foundations of six of them presented new and extraordinary difficulties of construction, owing to the existence of a bed of boulders below a shifting sandy bottom, to the sudden rising of the water, to the great velocity of the current at times of flood, and to the immense fields of ice which float down at the end of the winter season. Nos. 1 and 2 piers were founded easily on the rock at low water. No. 3 pier was founded in 23 feet of water at ordinary water stage. A wooden caisson without a floor was sunk on the site, the decomposed limestone within it was excavated by divers till solid rock was reached, and the crater was filled with concrete and two courses of stone laid upon it. The foundation was then ready for pumping out the water ; but the river suddenly rose 26 feet, and crushed the caisson. On the subsidence of the river, the foundation proving uninjured, the pier was built on a caisson boat and sunk on the spot. No. 5 Pier. —The rock was here 68 feet from the surface. The BRIDGE WORKS IN THE UNITED STATES. 11 compressed-air system was, in sinking the foundation, combined with Eads' sand-pump and air-lock at the bottom of the caisson, and a peculiar ' boulder sh jft,' with a separate lock, was designed to get rid of the boulders. Piers G, 7, and 8 are alike in the character of their foundations. Inside a circle of piles a caisson was sunk about 30 feet, by dredging, and stones were pitched round the piling as the caisson sank. This was continued till stone began to appear in the dredger buckets, which was a sign that the ' rip-rap ' had begun to pass beneath the piles. When this took place, dredging was stopped, and bearing piles were driven down to the rock and cut off at the level of the bottom of the caisson. The pier was then lowered on the top of the pile-heads, and the caisson being filled with stones, the foundation was complete. The superstructure was erected on three temporary piers of piling, protected by cribwork, under each river span. On these supports Howe truss spans, 80 feet in length, were placed; and from this foundation sprang the ' false work ' or centering on which the iron superstructure was put together. The approaches of the bridge are upon forty iron tressels, and, including these tressels, the bridge is 6,570 feet long. Its entire cost was about K2,250,000, or double the original estimate. This excess was due to tlie great and unforeseen difficulties encountered in constructing the foundations. St. Louis Bridge. (Visited November, 1873.) — The Mississippi at St. Louis is confined to a single channel, 1,600 feet wide and 8 feet deep at extreme low water, by an embankment or levee on the Illinois side, which is carried up to above the level of extreme high water, at which time the width is augmented to 2,200 feet. Both shores are revetted below the low-water line with rubble stones, and protected by the wharf pavements above that line. The extreme range between high and low wat(3r is 41 feet. Owing to the narrow gorge through which the whole volume of the Mis- sissippi flows, the variations in the bed of the river are very great. Captain James B. Eads, M. Inst. C.E., the distinguished Engineer who designed the bridge and superintended its construction, in- formed the Author that a rise of 13 feet less than high- water mark caused a scour of 18 feet, and that in the freshet of 1870 the scour reached a depth of 61 feet below low- water mark alongside the east pier. These facts induced him to believe it possible, that the scour at times of extraordinary high flood might extend even to the rock itself He therefore determined to establish the piers and abutments on the rock ; an* his was done by means of caissons provided with air chambers and locks at depths, for the east pier T^^..,- 12 OTHER SELECTED PAPERS. and east abntment, reaching 136 feet below high- water mark, or 110 fe*^t from the surface of the water, when the foundation work was actually performed. This feat, which was satisfactorily executed in 1870-71, is quite unprecedented in the annals of engineering.^ The piers and abutments are composed of coursed rubble masonry up to low- water mark. Above this level they are faced with grey granite from the State of Maine, which cost £10 per cubic yard in situ. The interior of the work is of magnesian limestone. The massive appearance of the granite rock facing, and its close joint- ing, are very striking;. The contract prices and the total quantities of the steel and ironwork required for the bridge are as follows : — 2,500 tons of steel, at £60 per ton . 500 „ wrought iron fit £40 per ton . 1,000 „ roUe'l iron, at £28 per ton . 200 „ cast iron, at £16 per ton •) I of 2,1 000 lbs. of 2,240 lbs. The bridge has three spans, each formed with ribbed arches made of cast steel — a novelty in bridge-building. The centre span is 520 feet and the side ones 502 feet each in the clear. The rise of the centre arch is 47^ feet, that of the side ones 46 feet each. These are by far the largest arched spans in the world, and, under the able direction of Colonel Flad, Captain Eads' chief assistant, they are now being rapidly erected gradually from each pier and abutment, without the aid of centering.^ Each span is composed of four double ribs of steel (well braced together, at their relative distances from each other), and the tubes forming them are jointed butt to butt. They are clasped together by wrought-iron couplings (which proved to be much better than steel), furnished with parallel grooves corresponding with similar grooves on the tubes. Steel pins, varying from 4-^ inches to 7 inches in diameter, pass through the centre of the couplings and the ends of the tubes at every joint. The vortical bracing between the upper and the lower tubular ribs — which are 1 2 feet apart from centre to centre — convert the two members into a single arch. ' Capt. Eads* Reports to tlie Illinois and St. Louis Bridge Company from 1868-71, containing a full account of tlie foundations of the bridge, are in the library of the Institution, and the most important of them will be found in " Engineering." 2 All details concerning the erection of the arches are given in a valuable Paper read before the American Society of Civil Engineers by Mr. J. C. Cooper, C.E., and published in " Engineering " iu January 1875. BRIDGE WORKS IN THE UNITED STATES AND IN CANADA. 13 At the time of the Author's visit two of the openings were already spanned by the steel tiibes, which are all 18 inches in diameter and 12 feet io 13 feet long, bnc of thicknesses varying from 1 ^ inch to 2| inches. I'he archcp are to carry a double railroad track, and above the track a roadway, 54 feet wide, for earria£;e8 and foot-passengers. Captain Eads hoped to bo able to opjn the bridge in tho summer of the following year. As fc^urteen railroads were waiting to make use of it, he was of opinion that the Bridge Company would eventually secure a good di/idend on their capital, al- though, from causes too numerous to mention, the outlay on the bridge had already considerably exceeded the original estimate. The extreme range of temperature at St. Louis is 160°; and it is calculated by Captain Eads that at 140"^ the arches will rise 8 inches, and that at 20° they will fall as much below the point at which they will be maintained at a medium temperature. Since the above wr.s written, the Author has received a letter from Capt. Eads, dated St, Louis, loth July, 1874, in which he says : — "My bridge was thoroughly tested on the 2nd with 560 tons of engines and 140 tons of tenders. This weight of 700 tons was run, first on one track on each span and then on the other, to pro- duce twisting of the arches, and then it was divided into two trains (seven engines and tenders in each), and these were advanced abreast on to each span to produce the greatest distortion of the curve of the arch, and finally each arch was covered with the trains. Tho latter produced only 3i inches deflection on the 520 feet span and 3;^ inches on the other two. No lateral move- ment could be detected by the instruments under the effect of the side-loading or twisting strain. The deflections were almost in exact accordance with the theoretical computations. The bridge was opened on the 4th July with great enthusiasm, a procession being formed of all trades and callings, which was five hours in passing a fixed point. It was estimated to be 15 miles long, and passed over the bridge and back." , • . Eoebling's Kailiioad Suspension Bridge (single track) over the Niagara River. ( Visited 10th October, 1873, with Mr. McAlpine, M. Inst. C.E.^ — This bridge has one span of 800 feet, which weighs as many tons. The height of the tower on the American side is 88 feet, and on the Canadian side 78 feet. The bridge, which is 24 feet wide, and has a road for carriages suspended 28 feet below the railway line, is hung on four wire cables each 10 inches in diameter. Their com- bined ultimate capacity is about 12,400 tons. To preserve them I:'! 14 OTHER SELECTED PAPERS. from rust they are covered with a tliick coating of hydraulic cement. The old timber-work of the load way, which is 250 foot above the river, is now being r^rioved an''. leplaced. Trains passing over the bridge are restrict id to a speed not exceeding 4 miles an hour. The first locomotive passed over it in March 1855. The cost of its construction wap £96,000, and the railway companies using it pay an annual toll of £9.000 a year. The road and passenger tolls bring in about £2,000 a year in addition. The rise and fall at the centre of this bridge is stated by Mi", Eoebling to be 27 inches under a change of 100° of temperature ; that is, the roadways are 2^ feet higher at zero than at a temperature of 100°.i International Eailroad Bridge (single track) over the Nia- gara, FROM Fort Erie to Buffalo. ( Visited lith October, 1873.) — This bridge is being built by a company, of which Mr. Brydges, Assoc. Inst. C.E., is President, and Mr. Hannaford the Engineer- in-Chief. The chief contractors are Messrs. Gzowski and Mac- pherson. By common consent, the chief credit in overcoming the extraordinary difficulties which beset the building of the piers of this bridge is due to Colonel Gzowski, upon whom all the practical operations devolved. The river Niagara at Fort Erie is about 1,900 f^et wide, and its depth ranges from 16 feet to 48 feet. The vatiation in the level of the river does not exceed 2 feet when uninfluenced by the wind. Its bed 'ionsists partly of rock, and partly of clay and large boulders. The normal current is 5J miles an hour, but during south-west gales it sometimes attains 12 miles an hour — when the water has risen 4 feet in a few hours. With such unusually strong currents, and with ice floes often 3 feet thick to contend against in the winter months, the founding of the piers was no ordinary task. Five of them on the Canadian side are built on the rock, whilst the three on the United States side rest on bearing-piles. The masonry was got in by means of outer and inner caissons. The anchoring of the former, while being sunk in place, was a most difficult operation, and quite unique in ci *- racter as an engineering feat. • , * The main bridge has nine spans, varying from 180 feet to 250 feet, and is 1,968 feet long, including the abutments; but ' For a detailed descriptiou of the state of this bridge at the time of the Author's visit see letter at page 157, vol xviii. of " Engineering," addressed by Mr. Thos. Curtis Clarke, M. Inst. O.E., Philadelphia, to the Minjster of Public Works, Caur.da. RIVERS AND CANAL, IN THE UNITED STATES AND IN CANADA. 15 including the length of the bridge across Black Rock Harbour, or the Erie Canal (600 feet), and the embankment joining the two bridges, the total length of the work is 3,650 feet. The iron superstructure, all from the Phoeuixvillo Works, is known as the ' Pratt ' or quadrangular truss. Its great strength is due to its depth, which in the centre of the 240-feet spans is 26 feet, and in the centre of t^e 'draw' 35 feet. It only weighs 1^ ton per lineal foot, and was put in place by mooring watertight caissons between the spans, and then building a platform on them to the required height. By means of hydrants in the caissons they can be sunk to any level and be easily removed. The draw or swing is 362 feet long, and can be worked either by hand or by steam ; by the latter it can be swung in about a minute. Since the above was penned, Colonel Gzowski has published a most valuable description of the International Bridge,^ in which he states that it was opened on the 3rd of November, 1873, and that the cost was about £300,000, including extras and interest on the outlay during construction. It was intended by the Author that the foregoing Notes should be oflfered as a contribution to tl a discussion on Messrs. C. D. and F. Fox's (MM. Inst. C.E.) Paper on ' The Pennsylvania h'ailroad "; '^ and if they are still regarded in that light, as he would desire, the scantiness of his remarks on the important subject of railway construction in North America will be explained. II.— RIVER AND CANAL WORKS. (Plate 6.) The St. Lawrence and its Tributahies. The St. Lawrence He to Fond-du-lac, 2,384 statute miles. 2,383 miles. From Superior, there are of open navigation, the distance is 1,942 navigation extends from the Straits of Belle- at the head of Lake Superior, a distance of The distance from Belle-Ile to Chicago is the Straits of Belle- He to the head of Lake 71f miles of artificial navigation, and 2,312^ From the Straits of Belle-He to Liverpool, geographical, or 2,234 statute, miles. ' This work is in the library of the Institution. * Vide Minutes of Proceedings Inst. C.E., vol. xxxix., p. 62. 16 OTHER SELECTED PAPEK8. Table of Distances, Compilkd from Canadian Blue-Kooks. , To Sections of Navigation. Statute Miles. From Inter- mediate. Total from SiralU of Belle-Uo. Streits of Belle-Ile Quebec .... 1 River and Gulf of \ St, Lawrence (River St. Lawrence 826 826 Quebec .... Three llivers . . ] to Three Rivers (highest tidal flow) Head of tidal flow 74 900 Three Rivers . . Montreal . 1 to head of ocean I navigation . 86 986 Montreal . Prescott Canal section . 119 1,105 Prescott Kingston . rHead of River St.j Lawrence . ./ 59 1,164 Kingston . Port Dalhousie Lake Ontario . 170 1,334 Port Dulhousie Port Colborne . Welland Canal. . 27 1,361 Port Colborne . . Amherstburgh . Lake Erie . 232 1,593 Amherstburgh. Whulsor Detroit River . 18 1,611 Windsor St. Mary's Island . Lake St. Claire . 25 1,636 St. Mary's Ifako St. Claire, and the Detroit river. The navigation is eaisy throughout, except on Lake St. Claire, where there are extensive sandbanks, covered with a depth of water vary- ing from G to 10 feet. Previous to 18r)8 niucli inconvenience was experienced in navigating the lake from the insufficient depth of water; but at the end of that year the Governments of the I'nited States and of Canada dredged the navigable channel to a minimum depth of 12 feet, and to a minimum width of 300 feet. In con- sequence of the improvements alieady ellccted, vessels carrying 300 tons of cargo can now pass from Lakes Superior and Michigan to Montreal without breaking bulk; and it is confidently antici- pated that in less than five years the additional works of improve- ment which have been referred to, as being either already in progress or in contemplation, will be completed, and thus enable vessels of 1,200 tons burthen to navigate freely between the same points. By far the best and cheapest, as well as the shortest, water route for the transit and exportation of the produce of the north-west of America will then be by the improved Welland and St. Lawrence canals to Montreal, and thence directly to Europe by ocean steamers of tho largest class. It has been aptly stated by Mr. John Young, M.P., of ]\Iontrcal, that a vessel from sea in the port of IMontrcal is 120 miles nearer to ports on the lakes than are any of the seaports in North America; while tho distances from Chicago, or from any other lake port, to Liverpool, is 480 miles less by Montreal than via tho port of New York. The Sault St. Marie Canal, 1 mile in length, and 18 feet lockage, avoiding the Sault St Marie, and uniting Lake Huron and Lake Superior, was constructed by a company with tho aid of the United States Congress. The Erie Canal. — Tho downward movement of freight of all ki^.ds by the Erie caaal from Buffalo and Oswego to tidewater, in 1873, was 2,466,022 tons. This canal was constructed in 1825, by the State of Now York,^ for tho passage of vessels of 60 tons ; ' The total cost, including maintenance and mana^^ement to the Bame date of all the New York State Canals, which have a combined length of 907 miles, was c 2 20 OTHER SELECTED PAPERS. but by tho year 1HG2 it was snfficiontly enlarged to allow of the passage of vchhoIs of 240 tons. The trunk lino of canal, as it may bo called, oxtondH from Buffalo on Lake Erie, from Oswego on Lake Ontario, and from Lake Chan)j)lain to Al])any on the Iliulson river, a combined length of 45.5 miles. Tho distance from Albany to >.'ew York by the Hudson river is 145 miles. D1MKN8ION8 and Capacity of tho Eiiik Canal and of its Two PlUNCIPAL FeEDEUS. Linglh III Miles. Size of Canal. No. and Size of Locks. Rise Locality. Width on Surfoce. Width on Bottom. Depth of Water. No. of Lucks. Length. Width. of Lockage. Buflfalo to Albany . Oswego to Syracuse Lake Chauiplain to"l Albany . . ./ 351 SB 66 Feet. 70 70 50 Fret. 56 56 35 Feet. 7 7 5 72 18 20 Feet. 110 110 100 Feet. 18 18 18 Feet. 655 155 180 455 Tho cost of construction, maintenance, and management of this length of 455 mile.^ up to tho 30th of September, 1873, amounted to $87,21)9,924, or £17,460,000, EicnELiF<:u River and the St. Ours and Chambly Canals. — This route of navigation extends from Sorel, at the confluence of the St. Lawrence and Richelieu rivers, 46 miles below Montreal, to the oiitlet of Lake Cham plain, a distance of 81 miles. Thence the line of navigation is by Lake Champlain and the Champlain and Erie canal (alieady noticed) to Albany and New York. The Richelieu ottnal has ten locks, with a total rise of lockage of 79 feet; and vessels of 300 tons, 116 feet long, 23 feet beam, and drawing 7 feet, can be passed through the canal from end to end, a distance of 44 miles. The cost of the Richelieu canal works to the 30th of June, 1867, was .8756,249. $107,906,763, or £21,600.000, and the total receipt from tolh $97,025,066, The total freight service on all these canals for the year 1872-3 was 6,673,370 tons, including timber, vegetables, food, machinery, manufactures, and merchandise of every description, the value being estimated at $220,913,321, and the tolls collected amounted to $3,072,411. In tho same year, and included in the tonnage, 2,200,000 quarters of wheat and 453,370 barrels of flour (= 3,964,836 barrels in all) were transported from the United States and Canada to tidewater by the Erie canal. , rt *•> THE niVER ST. LAWRENCE AND ITS TRIBUTARIES. 21 Tlio total length of navigation between Montreal and New York by this route is 456 miles, divided thus : — Mllen. Montreal to flrHt lock on the Richeliou, at St. Ours ... CO Ht. OurH lock 32 Chiunl)ly ciuiiil 12 — 41 Chambly cuniil to frontior at north end of Lake Champlain . 23 Montreal to frontior 127 Frontior to New York 329 Total ... 456 After this brief description of the principal channels of com- munication, from the great fresh-water lakes of North America to the eastern seaboard, it may bo useful to refer to the relative traffic expenses of the most important of these routes as compared with each other, and with the route by rail between the same points, as well as to quote the following paragraphs touching on this subject from a lieport, dated 29th April, 1872, on the pro- posed enlargement of the Welland canal, by Mr. John Page, the Chief Engineer of Public Works, Canada. " Between the head of Lake Michigan and the eastern end of Lake Erie, the distance by water is about 1,000 miles; by land it is only about 500 miles; but even this advantage has not enabled the land routes to compete successfully with that hy water for the carriage of those heavy articles which constitute the main items of export. " It is nevertheless true that flour, animal food, and such other kinds of freight, as either require to be conveyed speedily to market, or the value of which will bear higher transport rates, are now frequently carried by rail. " During the season when navigation is closed, the movement by the land routes lightens the pressure on the water lines in the open season. Still, the producing powers of the West are increas- ing so fast as to threaten to outstrip all the existing means of getting the surplus to market. " The keen competition which exists for this vast carrying trade, has induced the State of iS'ew York to reduce the tolls on her canals, 60 per cent., with a view of regaining the large business w^hich has deserted them. "This was done in the early part of 1870; but although the eastward movement of the Erie canal has increased considerably since that time, it is quite probable that a large portion of this 22 OTHER SELECTED PAPERS. I : . is duo to the fact that the crop for exportation in 1871, was much larger than that for 1870. " Strenuous efforts are now being made to introduce steam power on this route, with a view of diminishing the time necessary to pass through it, and thus lessen the contrast in this respect, between it and the railways. A very largo premium has lately been oiferod by the State authorities, for any design that can be judiciously brought into use for this purpose.^ " The great length and limited capacity of this canal, has enabled the railways to take from it a portion of heavy freights, the carriage of which it formerly monopolized, so that it is ques- tionable whether oven the entire abolition of tolls, and the suc- cessful application of steam power, would do more than partly restore the traffic which it has lost. " In this connection it may be ob^rved that all the leading lines of commimication in the United States, oast of the Mississippi river, from the producing regions of the West to the Atlantic seaboard, cross the Alleghany range at some point, with the exception of the Erie canal and the New York Central railway, which are carried through a break in the chain, forming the valley of the Mohawk river. " This being the best possible route for a canal in that direction, gives it an advantage, for the western trade, over all other water oh inels in the United States ; still it does not present a continuous downward lockage towards tidewater ; the long level at Rome being higher than those to the east .and west of it — and although its draught of water is comparatively small, the supply is main- tained with great difficulty during dry seasons. " There cannot bo a doubt but that there will always continue to be a considerable competition, between railways and canals, for the , carrjdng trade eastward from the foot of Lake Erie ; but from the westward to that point the water route, although twice the length of that by land, will in all probability keep the load. " This may safely be inferred from the known characteristics of the navigation, and the large class of vessels employed on it. ' It has since been afflrmod on good aiitliority that the most economical mode of employing steam on the Erie Canal is in vessels carrying their own macliinery and 200 tons of cargo. The greatest obstacle to the development of steam power on the Erie and WoUand canals is the smallness of tlicir locks. The lust report of the Nov*- York State Engineer states that the progress made in the use of steam for towing warrants the belief that it will supersede all other kinds of motive power on the Erie canal. . . • RIVERS AND CANALS TN THE UNITED STATES AND IN CANADA. 23 tho some of which draw about 12 feet of water, and are capable of carrying from 40,000 to 50,000 bushels of wheat. " TL 1, together with tho rapidity with which vessels can bo unloaded, and allowed to proceed on their return voyage, and tho attractions of tho commercial port of Now York, must, to tho extent of these advantages, have a tendency to throw tho stream of trade towards Buffalo. " To the westward of this point the route to the heads of Lakes Michigan and Superior, is common to all ; so that the rivalry between tho New York State canals and those on the St. Lawrence for the carrying trade to tho seaboard, may very properly be said to commence at the foot of Lake Erie. " If vessels of the capacity above mentioned could proceed down- wards withoiit breaking bulk, until alongside the ocean-bound ship, a great object would bo achieved, and a route established which might reasonably be expected to defy successful competition for the cheap and rapid transport of the heavy and bulky articles of agricultural produce." In comparing the distances, and in calculating the relative cost of tho transport of grain by water and land carriage to the sea- board, tho Author has selected the famous port of Chicago — tho largest grain emporium in the world — as being the best point of CoMPAnisoN of Distances and Transit Charges from Chicago to tho SiiA'soAui) by Water and Land Carriage. To Montreal, by the lakes, the Welland and tho St. Law-j rence / To New York, by Buffalo, the Erie Canal, and the Hudson I river ) To New York, by the lakes, tho Welland, Oswego, and Eriej Canals, and the Hudson / To New York, by the lakes, tho Welland, tho St. Lawrence,^ llifhelii'u, Cliamplaln, and Eric Canals and tho Hudson ./ To New York, by railroad Winter souson Summer season DiBtance iD Miles. Expense per Quarter. 1,278 1,418 1,412 1,632 960 g. d. 4 7 5 7 5 1 5 11 8 Cost of Transport in 1872. ^'cZdingToUs ^'^ ^^''. ^^'\ ^^. '''°''\'''';^ "''"■; ^;} ft cent per ton per mile Ditto by canal and river, without tolls \ cent „ „ ' ' Tho charge for transport by steam power against the stream on the Rhone , from Aries to Lyons, a distance of 200 miles, is 1 cent (i 30 OTHER SELECTED PAPERS. l';\ ! at nearly equal distances apart along the whole length of the chambers. The puddled embankment wall of the canal is mostly founded in the bed of the river, and is carried up to a height of 2 feet above the level of high water. It is 10 foot wide at the top, has slopes of 1^ to 1, and is protected on both sides with " rip-rap " (rubble stones). The range between high and low water is 22 feet at Keokuk, and 12 feet at Montrose. The excavation of rock amounts to 400,000 cubic yards, and of loam to 800,000 cubic yards. The estimated cost of the canal, including ^259,000 (37,000 cubic yards at S7) for the excavation of a channel through a chain of rocks at Nauvoo, at the head of the rapids, opposite Montrose, is K3,200,000 (£640,000)— a sum nearly one- third in excess of the original estimate. The cost of the rock excavation, exclusive of cofferdams and pumping (which treldes the expense), has varied from H2"20 to H^'SO per cubic yard, and the earth excavation from 30 cents to 65 cents. The interior of the embankment (derived from the excavation) cost 70 cents per cubic yard. The cost of the cut stone masonry, from quarries in the neighbourhood, was KlO per cubic yard, and of the concrete masonry K4. Major Stickney deprecates the system of executing hydraulic works by contract, and is of opinion that the canal could have been executed at more than 25 per cent, less if, from the first, and as is now the case, the work had been carried on under the immediate orders of the Engineer. The Illinois Eiver. — At 145 miles below the Des Moines rapids, and 24 miles above the Missouri mouth, the Illinois river joins the Mississippi after a course of 450 miles through the rich and fertile State of Illinois. A description of the lower part of the river, and of the plan proposed to render it navigable for large steamers, in connection with the improvement of the Illinois and Michigan canal, is referred to in the following extracts from the Eeport of General Humphreys, the Chief of Engineers of the U.S.A., dated 13th May, 1867 :—' , . " The distance from Grafton, at the mouth of the Illinois to the outlet of the Illinois and Michigan canal at La Salle, is 224 miles. The difference of level between the two points in the plane of low water is 29 feet. The river varies in width from 500 feet to 1,400 feet. -« .. ^. -v " In ordinary and high-water stages it affords good navigation for the largest class of steamboats used on the Mississippi ; while at ' Vide Annual Reports of the Chief of Engineer:;, .vhich may be consulted in the library of the Institution. i::il I RIVERS AND CANAI,8 IN THE UNITED STATES AND IN CANADA. 31 low water it can only be used by the smallest class of flat- bottomed boats. The whole distance, from the mouth of the Illinois river to Bridgeport, near Chicago, by river and canal, is about ;520 miles, and the lockage between the two points (ordinary water level of Lake Michigan and low water of the Mississippi) is about 170 feet, which, by making a through cut from Chicago river to Lock port, on the Des Plaines river, would be all a descending lockage, with the lake as a summit. " General Wilson recommends the improvement of the Illindis river by a system of locks and dams, and that the navigation be extended from Lockport to Chicago by the enlargement of part of the Illinois and Michigan canal, giving a depth of 7 feet, both in the river and canal, with locks 350 feet long and 75 feet wide. " The distance from La Salle to Chicago is 07 miles. It is pro- posed to cut down the present summit to low- water level of the lake. With the exception of two short canals, it is deemed ad- visable to abandon the old location, and to improve the natural channel of the river by locks and dams, they being less expensive than the enlargement of the original canal. " Estimated cost of canal frcm Bridgeport (4 J miles from Oliicago) to Lockport, 29 mile.i loug, 160 feet wide, and 7 feet deep Improvement from Lockport to La Salle . River improvement from La Sallo to Grafton Total .... Being about $68,000 a mile." 10,098,000 8,118,200 3,123,796 $21,3;?9,996 (£4,207,999) Since the above report was written, the canalisation of the river below La Salle has been begun, and the first slack-water pool has been created over a length of 28 miles by the con- struction of a lock and dam at Henry — a work which was suc- cessfully completed at an expense of ^400,000 (£80,000). The lock at Henry is 350 feet long by 70 feet wide ; the side walls are 30 feet high, although the lift of the lock is only 6 feet. A sJTuilar lock has been commenced at Copperas, 61 miles below Ft^nrj; and when this and three other shave been completed, at intervals apart of 61^ miles, 29i miles, and 41 miles respectively from Copperas, thus converting the lower half of the Illinois into a series of five pools, each with a lift of 6 feet, vessels drawing 6 feet of water, and carrying from 1,000 tons to 1,200 tons, will be 82 OTHEn SELECTED PAPERS. iiiip al)lo to navigate at all soasonK between the lllinoiH mouth and La Salle, Until, however, the improvements recommended by General "Wilson, between La Salle and Chicago, have been carried out, the dimensions of vessels on that part of the route must be restricted to the size of the locks of the Illinois and Michigan canal, which are only 110 feet long by 18 feet wide. Hitherto, the only executed portion of the proposed improvement, between La Salle and Cliicago, has been the cutting through the summit level of 26 miles which divides the valleys of the St. Lawrence and the Mississippi. This work was performed at the expense of the city of Chicago, as it was considered the best means of getting rid of the sewage matter of the city, and was completed at an expense of >}3,301,000 (£G<30,000) in 1871. TiiK IMiciiioAN Canal. — By moans of this cut, the bottom of which is 8 feet below the level of Lake Michigan, the Chicago river, with most of its impurities, and a clear stream from Lake Michigan itself, now flow into the Michigan canal, and thus help to feed the Illinois river. The real importance of the improvement of the Michigan canal and the Illinois river can only be properly estimated by regarding it as completing a system of water com- munication between the east and the west. The Mississippi mouth has ceased, it is alleged, to be the great outlet for the trade of the Upper Mississippi and Missouri. The present course of trade from these vast regions indicates that it is gradually being diverted to the east, and abandoning its natural course by New Orleans and the mouth of the Mississippi, which is inaccessible to the large ocean steamers now trading to Boston, New York, Baltimore, and Philadelphia. The improvements up to this time, excepting those already mentioned at Eock Island and Des Moines, have been confined to the dredging and scraping of bars, the removal of snags, and the cutting of trees to prevent them from forming new snags. ^ Dredging and scraping are mere palliatives, and if carried on by fifty dredgers, instead of by the solitary machine now employed, but little impression would be made on the shifting sandy bars which stretch across these mighty rivers in innumer- able places, and, at times of low water, make the river impassable ' From June, 1869, to June, 1870, four snag boats, wiiich are very ingeniously contrived, removed 3,031 sungs, weighing 60,000 tons, and cut down 33,.')00 trees in ttie Upper Mississippi, Missouri, and Arkansas rivers. The annual expense of working these four snag boats, the cost of which was 100,000 dollars each, is $340,000, and of the dredger $60,000, or $400,000 (i;80,000) in all. HI THE MISSISSIPPI AND ITS TRIBUTARIES. 88 to craft larger than a fishing boat. In respect to this discouraging condition of tlio Upper Mississippi and Missonri, Colonel Macomb in his ]{eport to the Chief Engineer, on the 20th of September, 1870, remarks : — " The works of improving the western rivers belong to the class of works which may be considered as indefinite or admitting of no permanent completion. It is indeed in the very nature of these great rivers, flowing through vast bottom lands, that such should be the case ; for improve the channel as we may one season, in the following year it will very likely be found that some of the im- proved reaches of channel have been abandoned by the river, and a channel chosen with dangers in it requiring a repetition of our labours, or new improvements." Thk Lower Mississippi. — It has been already remarked that the true Mississippi begins at the confluence of the Missouri and the Upper Mississippi. . • Distances and Inclination at Hioh Wateh. Inter- tncdiuto Distances. From the Missouri Mouth. From tho MlHslsHinpl Mouth. RlRht or Left Hanlc of the Ulver. High Water above the Gulf of Me.xlco. Slope per Mile. Mouth of the Missouri . Miles. • • Miles. MilPS. 1,286 right Feet. Inches. St. l.ouia .... 16 16 1,270 right 408 • • Mouth of the Ohio ( Cairo) 173 189 1,097 left 322 6 „ of the Arkansas. 405 594 692 right 149 5 „ of the Red river 376 970 316 right 49 3} New Orleans 211 1,181 105 left 15 2 Head of the passes ofi the Mississippi . . / 105 1,286 •• •• . . 1} • St. Louis. — This important city of four hundred and fifty thousand inhabitants is situated on the right bank of the river in the State of Missouri, and is the largest inland city in the United States.^ ' The celebrated Horace Greely, late Editor of the " New York Tribune," thus describes " the future great city " in a letter to Mr. L. U. Beavis, of Missouri, on the 4th of Feb., 1870 : — " I have twice seen St. Louis in the middle of winter. Nature made her the focus of a region embodying a vast area of the most fertile soil on the globe. Man will soon accomplish her destiny by rendering her the seat of an immense industry, the home of a far-reaching, ever-expanding commerce. Her gait is not so rapid as that of some of her Western sisters, but she advances steadily and surely to her predestined station of the first inland city on the globe." [1874-76. N.S.] D ■ !! ai OTHER SELECTED PAPKU8. It 18 16 miloH from tho MisBouri month, and is now joinotl to the Illinois bank by tho most romarkahlo bridge of nuHlorn times. This bridge Iuvh already been ])riofly described. Ko other bridge spans tho Mississippi l)etwoen th'> mouth of tho IMissonri and tho Gulf of Mexico, a distance of nearly 1,300 miles. The Ohio River. — 'I'his river flows into tho Mississippi at (^airo, 173 miles below St. Louis. 'J'he average width of tho Mississippi between these cities is 4,000 feet, and the least depth at any point is 2 feet at extreme low water. Tho total area of tho Ohio basin is 214,000 square miles, and its annual discharge of water is l.')0,000 cubic foot per second, or one- fourth that of tho Mississippi. The Ohio is formed by tlie junction of tho Alleghany and Monongahela rivers at Pittsburg.' 'J'liroughout its whole length (967 miles) tho river flows with a gentle current uninterrupted by rapids, except at the Falls near Louisville. At low water the Ohio is a succession of long pools and ripples, with a current alternately sluggish and rapid. The bars in the upper part of tho river are mostly gravel and boulders, in tho lower part shifting sand. The range between extreme high and extreme low water is about 46 feet throughout the entire river. . Distnnco Fnll Fall per Depth. from in Mile in rittsburg. Feet. Inches. At Wlieeling .... . 45 feet . 91 miles 79 10} „ Louifiville, on the Falls . 42 „ . . 598 „ 308 H „ „ bolow them . 64 „ . . 601 „ 333 100 „ Evansville. . 40 „ . . 783 „ 384 n „ Paducah .... . 51 ., . . 920 „ 418 2i „ Cairo (mouth) . . . 51 ,. . . 967 „ 427 2 The usual range is 25 feet. The width of the river varies from 1,200 feet to 3,000 feet. Proceeding upwards, the least low-water depth on the bars from the mouth of the river is, to Paducah, about 3 feet; to Louisville, 1^ foot; to Cincinnati, 2 feet to 2^ feet ; and to Wheeling, 1 foot. The business on the river is so arranged, that, at periods of very low water, all through steamboat traffic on the Upper Ohio ceases. The great bulk of the river traffic is, however, carried on " The Alleghany river, 290 miles long, is navigable for steamers for a distance of 259 miles abovn Pittsburg. The Monongahela river was * slack watered * in 1842 and 1856 for 84 miles above Pittsburg by the construction of six dams and eight locks Six of the latter are 190 feet long by 50 feet wide, and the other two are 250 feet by 56 feet. The cost of the work was about $600,000 02120,000). RIVERS AND OANALS IN THE UNITED STATES AND IN CANADA. 35 91 when tho depth o^ water is ',\ foet or more in the channels, which is on not less tlian two hiinelrcd and sixty days in tlic year. I'ho FallH of tho (^liio at LouiHvillo, which descend 25 feet in 3 miles, and which have been called a natural rook dam, are not navigable at extreme low water. At very high water any craft can pass them safely ; and at medium floods, with goml pilots, steamers and other vessels are taken over. In 1825, tbo Ijouisville and Portland Canal Comi.any obtained authority to make locks (184 feet by oO feet), and a cannl on tho Kentucky side, and tho first boat passed through in 1828. This canal is now superseded by an improved one with now locks, constructed in 18(30-GG by tho United States Government, under tho direction of General G. ^Veitzcl, I .S.A., ut an expoiiKO of about i?l,800,000 (£3(;0,()0()), after nearly the same amount had been spent on the works by a private company. Tho following information concerning tho Portland canal was given to the Author by Captain Adams of the Corps of Engineers, U.S.A., who kindly accompanied him over the work of wh ch Captain Adams had then tho charge. The canal is 2. J miles long, and is cut mostly in rock through a neck of land, about 70 feet above low water, between two reaches of the river on the Kentucky shore. By it, a level of 20 feet is sur- mounted at low water, at which time there is a depth of G feet of water in the canal. Of this depth 2 feet are obtained by tlio back- water caused by a dam of cribwork (not. yet completed), wliieli crosses the river at the upper end of the canal. Near the Indiana shore this dam has an opening or ' chute,' 400 feet wide, for the passage of vessels when tho locks are not required. The canal is about 80 feet wide, and has vertical walls of masonry 12 feet high. The upper guard lock is about | milo above tho entrance to tho canal, and its gates being but little higher than the vertical walls will only be useful in case of repairs, and are of no service in dam- ming back tho water, which sometimes rises 42 feet above the falls. When the water rises to 12 feet in tho canal,' the latter is no longer used by vessels descending the river, as they can then run tho rapids without difficulty or danger. The two lower locks are 390 feet by 80 feet in tho chamber, and each has a lift of 14 feet.* The lower gates are 68 feet high to provide against high floods, which have been known to rise 65 feet below the falls. • AUIiougli tho looks of the Portland and Dea Moinca canals are the largest oanal-looks in the world, some of the steamers on th(3 Mirisissippi which trade between St. Louis, tho Ohio, and New Orleans, from their breadth of beam, D 2 » 36 OTHER SELECTED PAPERS. Il I hi I |! Vessels now p:vy 50 cents (28.) per ion for passing through the canal, but it is expected that this high rate will soon be reduced 60 per cent. Otheu Works of Improvement on the Ohio, — These are of slight importance, and have hitherto been confined to dredging the more obstructive bars, and constructing here and there what are called ' rip-rap ' dams (artificial dams of rubble stones), with a view of concentrating tlie flow of the streanx into comparatively narrow cliannels, to secure an additional depth of water. Although these measures are of a very palliative kind, they would undoubtedly improve the navigable channel of the Ohio, if carried out systematically year by year on a commensurate scale, throughout the entire length of the river. When it is stated, however, that an annual grant of only Si 00,000 (£20,000) is allowed for this work, it is not surprising that no one can say precisely how much real improvement in the river has been acliieved since the attempt to deepen the channel was begun. Various plans have been suggested by American engineers during the last half century to effect a radical and permanent improvement of the Ohio. Of these may be noticed : — 1. Mr. C. Ellet's plan of artificial reservoirs to store up water enough, when gradually drawn out at lov. -water seasons, to make a perennial flow 6 feet deep in tui, ;hannels. 2. The scheme of a continuous canal 200 feet wide on one side of the river. 3. The method of locks and dams similar to the actual navisra- tion on the Monongahela, and to that now under executioi. on tho Illinois river. Difficulties and objections are inherent to erch of these expe- dients, but of all the schemes proposed it is ^ vneraily believed by those who have carefully studied t)ie subjv „ thid locks and dams, with chutes so arranged that coal fleets migl'.t be ppssed from one pool to another without division, would be tho best and most economical means of securing the desired depth of water from Cairo to Pittsburg, say, 6 feet, at all seasons. This is the decided cannot pass through them. For instance, tho "City of Richmond" steamer, which the Author inspected at St. Louis, had the following d aaensions : — Extreme length „ width Load line Light line Iroff 340 feet. | 85 )* f 11 »> I 4 » Two 5-foet cylinders andj l()-ft?et stroke, Six boilers. Paddle-wheels, 44 feet in diameter. Burthen, 2,500 tons. Height, from water-line to top of funnels, 92 feet. Ditto, to top of pilot houae, tiU feet. THE MISSISSIPPI AND ITS TRIinTTARIES. 87 opinion of Mr. W. Milnor Roberts, the Engineer in charge of the Ohio river improvement, who, iu a report, dated the 11th of April, 1870, to General Humphreys, on the radical improvement of the Ohio, estimates the cost of the system as follows : — Pittsburg to Louisvillo 598 miles. 51 seta of locks double, 370 feet by 80 feet, and 300 feet by CO feet, with 6-fect lifts, including dams and chutes at . . . Loniavillo to Cairo 369 miles. 15 sets of locks, do. do., with dama and chutes at Extra length of dams below the falls . 334,357 = 17.052,207 334,357 = 5,015,350 1,710,105 $23,777,062 £4,700,000, or $23,550 per milo for 9G7 miles. So far as the Author has been able to learn, no works have 3'et been iindortaken for the improvement of the navigable channel of the Mississippi livor below Cairo, although at low water the depth on some of the shoals between that city and tho mouth of the lied river, a distance of 781 miles, does not exceed 5 feet. Surveys and projects are now J)eing made, however, for tho improvement of these bars. Tho width of the Mississippi at the Ked river landing is 3,020 feet at high water and 2,<)50 feet at low water. The distance from the mouth of the Ohio to tide- water by the Mississippi river is about 1,100 miles, and the average fall is at the rate of 3 inches per mile. The moan area of cross section at high water over this length is 105,000 square feet, and the mean annual rainfall 30;^ inches. The Arkansas River joins the right })ank of tho Mississippi at 405 miles below Cairo. The area of its basin, including that of tho White river, is 189,000 square miles, and the mean annual discharge is at the rate of 63,000 cubic feet of water per second. This river is 1,514 miles long; the width varies from 1,500 to 5,000 feet, and the least depth on the bars at low water is 1 foot. Tho estimate for its improvement for tho year ending the liOth of Juno, 1874, is ^100,000 (£20,000) for tho running expenses of four snag boats, five months each at S5,000 per month. The Rkd River joins the right bank of the Mississippi 781 miles below Cairo, and at 316 miles from the Mississippi mouth. It is 1,200 miles long, tho width varies from 800 to 2,000 feet, and the least depth of water on tho bars is also 1 foot. Tho area of the basin is 97,000 square miles, and the mean annual discharge of water is 57,000 cubic feet per second. 38 OTHER SELECTED PAPERS. 1'he only expenditure made by the Government for the im- provement of this river has been in the many attempts to remove the obstruction known as the " Eed river raft," which is composed of an immense accumulation of drift wood, partly sound, partly rotten, partly sunk, and partly afloat, but always advancing steadily up the river. Its length in the summer of 18o4r was 13 miles, and it had then advanced to a point 53 miles above Shreveport.' The Deli'a (Plato 7). — Just below the confluence of the Eed river is the first of the bayous,- w^hich, fed by the Mississippi, discharge into the Gulf of IMexico. Below this point the great river receives no appreciable increase from tributaries. It has, therefore, fov these reasons been generally considered the head of the delta. On the assumption that a delta begins where it first sends off a branch to th(! sea, at the head of the bayou Atchafalaya in tliis instance, the delta of the Mississipppi has an area of 12,300 square miles, of which one-third is composed of soa marsh. It is contended by some writers, however, that the origin of the delta is 3 miles below Capo Girardeau (47 miles above the mouth of the Ohio), where the waters of the Mississippi used to escape into the St. Francis, and thence through the Arkansas valley into the Atchafalaya, &c.; and that, therefore, the area of the delta is really 38,706 square miles. This is stated in a recent paper by I'rofessor C. Forshey. Between Bayou la Fourche (the last of the outlets) and Fort St. Philip, the Mississippi flows through a tolerably uniform channel, averaging at low water 200,000 sqiiaro feet in cross section, 2,470 feet in width, and 12i) feet in depth at the deepest part. In the Iot,- water stage, these measurements are 163,000 square feet, 2,250 feet, and 114 feet respectively. Lkvkes and Cut-offs. — Between Cairo and Fort St. Philip 1,600 miles of levees, or embankments, have been constructed to protect the adjacent lands from overflow ; but the system was so imperfect in 1869 (and the same may even now be said) that General Abbot, U.S.A., reported that an outlay of K38, 230,000 was required to raise the existing levees in the states of Arkansas, Mississippi, and Louisiana, (^19,0(50,000, K4,150,000, K15,020,000 resi^ectively) to their proper height. This sum, at the estimated cost of the work, ' Since tliia was written the Autlior has been informed by General Humplircye that the laft liaa lx;en removed, and that by annual grants from Government ita reformation iu to be {ircvintcd. - A bayou in liOuisiauu means a stream not so large as a river, and a crook ()roporly no called. RIVERS AND CANALS IN THE UNITED STATES AND IN CANADA. 39 viz., 40 cents per cubic yard, represents embanking to the amount of 95,000,000 cubic yards.^ The efficacy of ' cut-oifs ' as a means of relief from floods has been contested by many authorities on the 'regime' of the MiKsisHip{)i. In December 1874 General M. Jeff Tliompson, Chief State Engineer, reported to the Governor of Louisisina that two out of the six cut-offs, made below the mouth of the Arkansas and Tunica since the days of steamboats, were fast elongating themselves, at the ex- pense of the levees. With regard to these this engineer remarks that there are none from Cairo to Memphis on the left bank, nor from ^icksburg to Baton Eouge, except a few private ones; but that there has been a system of levees along the whole of the right bank, from Commerce to Fort Jackson, near the mouth of the Mississippi. He also adds that from Memphis down to the mouth of the Tazoo, and from Baton Kouge down to Fort Philip on tho left bank, the levees form a complete system. An aggregate length of 107^ miles of levees — wings and main line included — were lost from October 1866 to October 1874, in consequence of the caving of the banks of tho river in tho State of Louisiana. During the disastrous floods of the spring of 1874, a crevasse of unusual magnitude occurred at Bonnet Carre, in Louisiana, of which a detailed account (from tho Levee Commis- sioner's report) is given in Ajipondix I. Twenty miles below Fort St. Philip, a great change takes place. (Plate 7.) The river widens to 8,000 feet, with a maximum depth of about 40 feet, and a cross section of about 250,000 hquare feet. It then separates into three principal branches, called from tho directions they take, the South- West Pass, the South Pass, and the North-East Pass, the latter sending off a branch called the Pass a I'Ontro. The dimensions of these passes are shown by the Table on the next page. The bars at the mouths, are composed of sand and soft mud, and are described in Humphreys' and Abbot's work as being pro- duced by sand and silt rolled along the bed of the river, and not by the precipitation of matter held in suspension by the outflowing waters. The length of tho bar of the South-West Pass, or the distance between the 18-feet contour lines, is 2^ miles. ' To the 1st of October, 1874, the Louisiana Levee Company, which was incori)orated iu February 1871, have built levees containing 4,823,012 cubic yards, at a cost of $2,520,G12, being at tlie rate of 58 cents (28. 4rf.) per cubic yard. General Al)bot'8 estimate was based on the heiglit obtained by the great flood of 18.'58, which has not been exceeded since, and an allowance was made of about 1 foot for a possible rise above that extraordiuariiy high flood. 111' 't i \r. 40 OTHER SELECTED PAPERS. Dimensions of the Main Passm of tho Misbissippi.' Pass. I^cngtli to outer crest of Bar. Mean Width. Mean Depth. Mean Area of Cross Section Proportion of Discharge, thatoftlio MitiBissippf being unity. Miles. Feet. Feet. Square feet. South-Weat Pass . . 17 1,200 58 70,000 •340 South Pass. . . 14 700 34 24,000 •080 Nortli-East Pass . . IG 2,500 37 92,000 •225 Pass k I'Outio . . . 15 1,300 36 47,000 •254 Remainder mi xinly through South-West Pass • •101 Discharge and VELoniriEs at tho head of tho South- West Pass, which delivers one-third of tlxe total volume of the Mississiiipi into the Gulf. The dis- char^ro through this Pass exceeds the entire volume of tho Danube. lUvor Stage. Usual Minimutn Discharga per Secund. Mean Voiocity per Hour. Discharge per Second. Mean Velocity per Hour. Flood Low water . Cubic Feet. 340,000 102,000 Miles. 4-9 14 Cubic Feet. 272,000 75,000 Miles. 3-9 1-0 The natural depth on tho South-West Pass is only 13j feet, but by the use of two eiteam-dredgers, or mud-scrapers, a depth varying ' Mr. G. W. R. Bayley, civil euginoer, New Orleans, an acknowledged authority on all matters connected with the Lower Mississippi, has lately directed attention to the fact that, while the high-water slope of tho river, from New Orleans to tho head of the passes, is only about 1 J inch to the mile for the whole river, tho high-water slope of the South-West Pass channel is about 2 iuches per mile ; of the Pass a I'Outre, about 2J inches per mile, and of the South Pass, about 2J inches per mile. It is well known, he maintaius, that the greater the normal quantity of water flowing in a sedimentary riVer, below its last affluent, the less will be its surface slope, and the greater its depth and Telocity of current and sectional area of channel. The width of the Mississipin river does not increase from the mouth of the Ohio down, but its depth does, below each affluent; while the surface slope diminishes, gradually, as far down as the head of the passes. See Table of Inclinations at page 33 ; also remarks on the same subject in Mr. Alfred Tyler's highly interesting Paper, on " The Curve of Denudation," Geological Magazine, vol. ix, pp. 392, 485. THE MISSISSIPPI AND ITS TRIBUTARIES. 41 from 16 to 18 feet was maintained over a channel from 200 to 800 feet wide, for the two working seasons previous to 1873, It is considered that by this means a channel 18 feet deep could always be maintained, at an expense of ^200,000 (£40,000) a year, a sum which includes the entire renewal of a steam-scraper every four years. The cost of the scrapers is ^200,000 each. They are arranged so as to bring up the silt, which has been agitated by the screw of the vessel, into the upper stratum of the outgoing current. In the channels where the machines ha/e been employed, the velocity of the surface is generally from 2 to 3 miles per hour ; but at 10 feet below the surface the velocity is reduced to 1 mile per hour ; and at the bottom, not only to zero, but occasionally on a rising tide,' and when the flow of the Mississippi is under 800,000 cubic feet per second, which is the discharge at ordinary high-water, the current flows in an inverse direction, or into the river. Hence the neces- sity of having the scraper vessels so contrived as to bring the mud, which has been stirred up by the screw, as near the surface of the water as possible. The machines only work on the crests of the bars over a length of less than 4,000 feet, and the current does the rest of the deepening. Major Howell, U.S.A. (Resident Engineer for the Lower Missis- sippi), informed the Author that each steamer removes about 10,000 cubic yards of mud a day, and that early last year, owing to ob- structions designedly thrown in the way of the navigation by the Towage Steam Company, which has a monopoly of the towing at the mouths, the scrapers were withdrawn to the Pass a 1 'Outre, where they worked for the remainder of the year. The natural depth of water on the bar of the Pass a I'Outre is only 1 1 feet, but the effect of the scraping was to deepen it to nearly 18 feet, over a width of about 200 feet, at the end of 1873, by which time the depth on the South- West Pass was again reduced to 13 feet, although vessels drawing 17 feet were actually then being drawn across the bar, through 4 feet of soft mud, by the Steam Tug Company. Fort St. Philii' Canal. — The majority of a Board of Military E: ^rineers, who assembled at the mouths of the Mississippi, in Kovember 1873, to consider and report upon the plan submitted by Major Howell for a ship canal, recommended Congress to construct a ship canal from Fort St. Philip to Breton bay ; and accordingly, on the 9th of February, 1874, a Bill was introduced into Congress which " provides for the construction of this canal, and its maintenance ' The tide has a mean tiec of 15 iuolies every twenty-four hours at the Missiasippi muuths. . 42 OTHEB SELECTED PAPERS. as a public highway." In the Bill it is enacted, — " That a ship canal to connect the Mississippi with the Gulf of Mexico, com- mencing at some convenient point on the river below Fort St. Philip, and terminating at some convenient point in Breton bay, shall be constructed and maintained at the expense and under the control of the Government of the United States : That the dimensions of the canal shall not be less than 200 feet wide at the bottom, and with not less than 26 feet in depth of water, with the necessary guard-gates, locks, &c., which may be neces- sary for the safe and convenient navigation of the canal." The estimate for the above work is K 10,296,600 (£2,000,000), which includes the cost of jetties for extending the canal into the deep waters of the Breton bay. Parallel Piers versus Caxal. — General Barnard, U.S.A., who was in the minority of the Board of Military Engineers, of which he was the President, is of opinion " that the con- ditions of the location and execution of a canal have received no adequate study," and he therefore demands "new studies ot location, and an entire revision of plans of execution." He is also in favour of an open river mouth rather than of a canal impeded by locks. He likewise agreed with the Author in the opinion, that the South Pass of the Mississippi should bo selected for a full trial of the jetty system, on the principle that it is more advisable, in an economical point of view, to improve the mouth of a minor branch of a river, rather than to grapple with the diflfi- culties at the mouth of a principal branch, if that minor branch debouches into deep water, and offers a sufficient breadth and depth of channel for the navigation till its bar is reached. The south branch has a width of from 600 to 800 feet, and a depth of not less than 26 feet throughout its entire length of l:J miles, excepting for about ^ mile at its bifurcation with the main river, where parallel training works would be necessary to secure the depth and width required. Although holding these views in favour of the South Pass, the Author is by no means opposed to the opening of the South- West Pass, by means of jetties, if it is considered that the far greater expense of construction in the first place, and of the maintenance of the works and channel afterwards, contingent on the improvement of the larger mouth, would bo compensated by the grander result to be ol)tained. Since these notes were written. Captain J. B. Eads has formally proposed to the United States Government to deepen the South- West Pass to 28 feet, for the sum of S 11,000,000, by means t.f parallel piers ; and a new commission, consisting of civil and WATERWORKS IN THE UNITED STATES. 48 military engineers, has boon named to report to Congress on the merits of all the plans of improvement yet devised for providing the river with a deep sea entrance. III.— WATERWORKS. Croton Waterworks, New York.- (Visited SOth December, 187;^, with Mr. G. M. Van Nort, Commissioner of Public Works, and Mr. Edtvard H. Tracy, Chief Engineer.) — The Croton Aqueduct, which supplies the city of New York with water, is a monument to the ability and skill of Mr. John B. Jervis, C.E., the designer and constructor of the works. The aqueduct was begun in 18:57, and finished in July 1842, with the exception of the Migh Bridge at Harlem, which was not completed till 1848, the water in the meantime being conveyed across the Harlem Valley by a tem- porary pipe. The following sketch of the priuc^'pal features of the aqueduct is abridged from Mr. Jervis's report of the 27th July, 1842, to the Water Commissioners, which has not yet been published in England.^ The Croton Aqueduct commences about 6 miles above the mouth of the Croton river, where a dam has been constructed to elevate the water of the river 40 feet to the level of the head of the aque- duct, or 16G feet above mean tide. The aqueduct passes along the valley of the Croton to near its mouth, and thence into the vf ,iley of the Hudson. The length, from the Croton dam to Karlem river, is 33 milefe, for which distance it is an uninterrupted con- duit of stone and brick masonry in hydraulic cement. Description of the Country. — The soil, earth, and rock of the country, from the banks of the Croton to the city of New York, are of one general character. The prevailing rock is gneiss, of great variety in quality. The surface is generally a sandy loam. Below it, soil, gravel, sand, boulders, or detached rock, have in most cases been found. A largo portion of the open cutting, and nearly the whole tunnel cutting, has been through rock, more than 400,000 cubic yards of which have been excavated. The general formation of the country is extremely irregular, and unfavourable for the economical construction of an aqueduct. Aqueduct. — The bottom is an inverted arch, the chord being ' A full description of tlio Croton Aqueduct in English, Gormrin, and French, by T. Schramke (London and Berlin, 185.^), is in tlie library of the Institution. Ill m 44 OTHF ICTED PAPERS. V 1 '^' ■ 1 1 ;h . sine 9 inches. The side walls rise g of the invert. The roofing arch is 6 feet 9 inches, and th' 4 feet above the s* semicircular, v/ith a as of 3 feet 8j inches. Thus the greatest interior height is 8 feet 5^ inches, the greatest width 7 feet 5 inches, and the area 6;J * 34 square feet. The inverted arch is of brick, 4 inches thick. The roofing arch is also of brick, 8 inches thick. The abutments are of rubble stone, with a brick facing 4 inches thick. In all cases a course of concrete in hydraulic cement was laid under the extrados of the inverted arch. The area of a cross section of masonry in the aqueduct is 42^ square feet. The proportion of the line of aqueduct masonry on foundati(m walls over valleys, to that in excavation, is about 1 to 8. The masonry of the aqueduct is covered with earth to a suificient depth to protect it from frost.^ There are sixteen tunnels on the line, varying in length from IGO feet to 1,263 feet, making an aggregate length of 6,841 feet. The height of the ridges above the grade level at the tunnels ranges from 25 feet to 75 feet. The foundation walls, in crossing uneven ground and ravines, are of dry masonry. Culverts. — To pass the streams that intersect the line, one hun- dred and fourteen culverts, varying in span from 1^- foot to 25 feet, have been constructed, at depths varying from 16 feet to 83 feet below the top covering of the aqueduct. Ventilators. — There are thirty- three ventilators to give free ventilation of air through the aqueduct. Waste Weirs. — Six are constructed on the line of aqueduct, so arranged as to allow the water to pass off when it rises to the proper height, with gates to draw off the water when necessary. Croton Dam. — The greatest height of the weir of the dam is 40 feet above the low-water level, and 55 feet above the bed of the river. The width of the masonr}' at the low-water line of the river is 61 feet. At 300 feet below the main dam, a second dam was constructed of timber, stone, and gravel, to deepen the water over the apron of the former, and form a pool to check the force of the water as it falls. From the main dam, which raises the level of the water of the river over a length of 5 miles, and forms a reservoir of 400 acres, the water flows into the bulkhead at the upper end of the tunnel, from a level averaging 10 feet below the surface. Aqueduct Bridge at Sing Sing. — The Sing Sing Kill, where it crosses the line of aqueduct, runs in a deep and narrow gulf, the bottom of which is 76 feet below the top covering of the aqueduct. Over ' The depth is uever lesi thau 8 feet. WATERWORKS IN THE UNITED BTATES. 46 this gulf an aqueduct bridge has been constructed of stone and bricJf masonry. Its centre arch has a span of 88 feet and a rise of 33 feet. Harlem River Bruhje. — The width of the river, where the aque- duct line crosses it, is t)20 feet at ordinary high-water mark, and its greatest depth is IG feet at very low tides. The high ground that bounds the north side of the Harlem Valley is very nearly on a level with the aqueduct ; and the width of the valley at the aque- duct level is about 1,450 feet, over which a bridge of the same length has been constructed. The south bank of the valley is here a bold, precipitous rock, rising to a height of about 220 feet above the river. Across the river there are eight arches, each of 80-feet span. On the south of this range of large arches there is one arch, and on the north six arches, each of 50-feet span. The archcB are semicircular, and their sofiSts are 100 feet above ordinary high water. The piers are founded partly on the rock, partly on bearing piles. All the masonry is of well-dressed granite. The space — 21 feet— between the parapets is arranged to receive and protect from frost two cast-iron pipes, each 4 feet in diameter, which are to lie at the level of 108*25 feet above the level of mean tide.^ This is 12 feet below the grade line of the aque- duct, to which the pipes descend from the gate-chambers at the end of the bridge. The object in using pipes was more effectually to secure the conduit from any leakage, that might eventually injure the masonry of the bridge, and it incidentally allowed the bridge to be constructed of less height. To make the capacity of the pipes for conveying the water equal to that of the aqueduct, an extra fall of 2 feet has been given across the bridge, and the aqueduct on the southern side of the river is constructed 2 feet lower than the regular grade to accommodate this arrange- ment. .:.;.. It was originally contemplated, and the work put under con- tract, to construct a low bridge with one arch for water-way ; but a supposed value, which was attached to the future navigation of the river, was so pressed upon the legislature as to induce them to pass a law requi-ring that the under side of the arches should be 100 feet above ordinary high water.^ ' These 4-feet pipra were never laid down, as two of 3 feet diameter were considered to be sufficient at first ; the latter still remain, leaAy for use again in case of need, but the water is now &:>nducted across the atiueduct by a 7J-feet pipe of boiler-plate. ' It may bo asked, why not have raised the bridge 12 feet more, to the grade of tho aqueduct, and thus have saved a fall of 2 feet, besides sparing the 46 OTHER SELECTED PAPERS. Manhattan and Olendenning Valleys. — After croBsing nailem Valley, the aqueduct of niasonry is resumed, and continued 2 miles, to the termination of the high ground on the north of Man- hattan Valley. This valley is f mile wide, iind 102 feet below the level of the aqueduct. The conduit of masonry here gives place to iron pipes, which descend to the bottom of the valley, and rise again on the opposite side, from which point the masonry conduit is again continued, and, crossing Glendenning Valley on arches, after 2 miles reaches the receiving reservoir at York Hill. lieceiving Reservoir. — This reservoir has an area of M acres, and a capacity of 150,000,000 imperial gallons. It is in two divisions, and is formed with earth banks, the interior having regular puddled walls; the outside, protected by a stone wall, has a slope of 1 horizontal to 3 vertical ; the face is laid in cement raortar, and the inside is dry ; the in^ide is protected by a dry wall, laid on the face of the embankment, which slopes li^ hori- zontal to 1 vertical. The embankments are raised 4 feet above the water line, and vary from 18 feet to 21 feet in width at the top. They are of moderate height for the northern division of the reservoir, which has a depth of about 20 feet ; but in a portion of the southern division, whore the depth is about 30 feet, they are 38 feet high above their base. Distributing Reservoir. — This reservoir is situated on the 5th Avenue, between 40th and 42nd Streets, and is 3 miles from the City Hall. It is built entirely of masonry, and covers an area of 4 acres, divided into two equal divisions, and has a capacity of 20,000,000 imperial gallons. It has a depth of 36 feet, and when full the level of the water is 115 feet above mean tide. Its walls rise 4 feet above the water line, and have an average elevation of 45^ feet above the level of the adjacent streets. Length of the Aqueduct. — The length of the aqueduct, from the Croton dam to the distributing reservoir, is 40^ miles. It is proper to add to this the length of the Croton reservoir, which is 5 miles, and extends 4 miles for the length of thfi large mains from the distributing reservoir through the central part of the city, making the total length of the main conduit nearly 50 miles. Grade Line of Aqueduct. — The general declivity of the aqueduct in expense of the two gat^-chambers ? Apropos of this question, Mr. Tracy has written to the Author as follows : — " It is impossible in this country to construct a conduit of masonry, of any considerable length, that will remain watertight. The contraction and expansion of the High Bridge, from the extreme heat of summer to the extreme cold of winter, is more than § inch by actual measure- ment." WATERWORKS IN THE UNITED 8TATE8. 47 in WesteheHtor County is 0*021 fcx.t per 100 foot (TlOO foot per niilo). The graclo from Ilarlom Kiver to Manhattan Valley is the same as the general grade of the aqueduct in WestchcHter County; but that from the Manhattan Valley to the receiving reservoir, 2 J miles, is 9 inches per mile. Coat. — Mr. Jervis concludes his Report by stating that the actual cost of the aqueduct, fiom the Croton dam to the di.Ntributing reservoir, inclusive, v^'as under K9,000,000 (£1,800,000), being within 2 per cent, of the original estimate. The following information respecting the present state of these works was obligingly furnished to the Author by Mr. Tracy. ^ addition to a new receiving reservoir in the Central Park,* .ich has an area of 106 acres, a depth of 3G feet, and a capacity of 1,000,000,000 gallons, a new storage reservoir at Boyd's Corners, in the Croton Valley, has been built to contain 3,000,000,000 gal- lons ; so that the combined capacity of the reservoirs, including the Croton reservoir or lake, is now 4,570,000,000 gallons.^ Ex- perience has proved that, as long droughts prevail during the summer and autumn, the quantity of water in the river is in- adequate to supply the daily needs of the city, and that, there- fore, the only way to secure a constant supply is by storage reservoirs, to be filled during the wet season. Preparations are accordingly being made for the construction of a third large reservoir in the Croton Valley, with a capacity of 3,700,000,000 gallons. When this is done, the combined reservoirs will be able to supply the city for eighty-two days at the present rate of consumption of 100 gallons per head, irrespective of the minimum quantity daily furnished by the Croton river in seasons of extreme drought, viz., 27,000,000 gallons. From 1842 to 1848, 18,000,000 gallons per day gave an abundant supply. At that time the city had about four hundred and fifty thousand inhabitants, and now, with a population of one million, the quantity consumed is sometimes 100,000,000 gallons per day. Thus, though the population of New York has little more than doubled since 1848, the consumption of water has increased fivefold. ' There are six 4-feet mains into and out of this reservoir (which was com- pleted in 1862), and the valves are so arranged that they can only be fully raised in one hour. * When the word "imperial" is not mentioned, it may be taken for granted that the gallons indicated are United States gallons, which compared with imperial gallons are as 5 to 6 : a United States gallon being equal to 231 cubic inches (the capacity of the old English wine gallon), and the British imperial gallon to 277 • 274 cubic inches. ir\ 'v. ,i ' l:ji Jiii 11 48 OTHEtl RELrCTlD PAPFRS. ■I I When tho aqueduct was built, it was supposed it would only deliver 60,000,000 imperial, or 72,000,000 I'nited States standard gallons, every twenty-four hours. Tho discharge was computed from formuleo based on the best-known channels at that time, but all of which were smaller than the Croton Aqueduct. Careful experiments on the present flow of water show that it can deliver 115,000,000 gallons every twenty-four hours, or 00 per cent, more than its estimated capacity.' The watershed of the Croton river is about iMO square miles, and the annual rainfall is 49 inches. At or near the sources of many of the tributaries there are natural lakes, varying in size from 50 acres to 500 acres. These basins are generally of great depth, and their waters, which are remarkably clear and pure, are derived either from springs in the lakes themselves > in the highlands near them. Tho new storage reservoir at Boyd's Comers has an area of 300 acres, and has been formed by building a dam across the west branch of the Croton river. The dam is about 700 feet long, and high enough to lift tho water 60 feet above the surface of the stream. The masonry wall of the dam, on its inner side, is for- tified by a watertight bank of earth, and a canal is cut through the rock at the northern end of the dam to allow the floods to escape over a rock surface into the river below the dam. The major part of the higher section of the city of New York, north of Manhattan Valley, is supplied from a > 'v high-service reservoir, into which water is pumped by steam from the aqueduct near 17:ird Street (close to the Harlem Bridge), whilst the extreme high points are supplied from a tank supported on a towor bull* to a height of 300 feet above the sea, near the site of the reservoir. The islands in the East and Harlem rivers are supplied with water by pipes, varying from 2J inches to 6 inches in diameter, from the shores of New York City. These pipes are generally about 1,000 feet long, and are laid on the beds of the rivers in depths of from 70 feet to 100 feet of water. Until very recently, they were either of cast iron, lead, or gutta-percha. The latter, which are soon abraded on a rocky bottom, are now being advan- tageously replaced by wrought-iron pipes. These are so elastic, and are so well protected with a casing of planking, that they can be readily laid, already put together, on the bed of the river, at a radius of 300 feet. Shortly before the Author's visit, ' > The flow in the aqueduct, which is never full, is at the rate of about 2i miles per hour. WATERWORKS IN TUE UNITED STATES. 4n it was decided to lay down a wrought-iron lap-wol 'od pipe of 6 inehes in diameter, made in the same manner as pipes for conveying steam, coupled together with screw conplings. Tlio operation was thus described hy Mr. Tracy : — The couplings wore strengthened and protected by heavy cast-iron sleeves, secured by lead joints, making the joints as rigid and stiff as any other part of the pipe, 'i'he pijjo was then placed in a heavy oak case securely ])olted and riveted together, and the space between the pipe and case filled with hydraulic cement. The pipe was put together in 02nd Street. When fitted up complete in the box, and the box thoroTighly saturated with coal-tar, it was then, by means of a powe:ful dredge with a steam capstan of lUO III'., hauling on a heavy chain cable fastened to the rocks on Black well's Island, drawn across the river. The dredge was assisted by three powerful steamboats, whieh in case of the breaking of the chain could have held the end of the pipe in position. The pipe as fitted up in the box was 1,;550 feet long, weighed over 200 tons, and was put across the river in water 100 feet deep. It was laid without any accident or injury, and it is believed to bo strong enough to withstand the anchors of any vessel which navigates tho East river. Six 4-feet cast-iron pipes are now being laid in tho lOth Avenue, between li;3th and 92nd Streets, preparatory to tho removal of tho aqueduct work over Glendenning Valley. This tedious and expensive work is necessitated by an Aot of tho legislature, which directs the Waterworks Department to remove the above-named portion of tho old viaduct, as it obstructs tho traffic from oast to west, and to replace it by a new one, or by pipes, below the newly- established grades of the streets and avenues, which now extend uninterruptedly from tho Battery Point to Kingsbridgo over Harlem river, a distance of 15 miles. Owin^' to an alteration in tho grade of tho 5th Avenue, it be- came necessary, about two years ago, to lower two 3-feet main water pipes about 4 feet, in a long cutting throiigh hard gneiss, between 68th and 72nd Streets. It was decided to lower these pipes with the water in them, and to continue their use while the operation was going on. Tho trench where they lay was widened on one side to allow them to be moved laterally. They were next placed upon saddles resting on greased skids, and moved over, one line at a time, by screw-jacks. Then, after being protected with timber while tho new rock trench was blasted, they were moved back, on greased skids, supported by blocking, to their original line, and lowered by screw-jacks into position. This delicate and :ili; [1874- 7o. N.S J fi r' 50 OTHER SELECTED PAPERS. In hazardous operation was successfully performed without accident to life, limb, or property. Mr. Tracy states, in one of his last reports to the Commis- sioners, after a personal inspection of the interior of the aqueduct, from end to end, that the brick facing of the masonry shows no sign of either wearing away or of disintegration, and that there is every reason to believe the whole structure, with proper care, will successfully perform the duties for which it was built for centuries to come. To the latter opinion the Author would add the remark, that all the important subsidiary works of the aqueduct which he inspected, and which have been but lately completed, appeared to have been as skilfully designed, and to be as imperishable, as the famous aqueduct itself. Chicago Waterwouks. — Hardly any one who has visited Chicago of late years can resist the temptation, when the name is men- tioned, of plunging into a mass of statistics, to enable those who are not acquainted with the marvels of the place to realise the fact of its amazingly rapid progress, from a hamlet of squatters in 1830, to a city of the first rank at the present time. The Author may perhaps, therefore, be excused in stating a few facts relative to the city of Chicago before referring, in some detail, to its water supply.^ The population of Chicago in 1830 was 1840 .. »» 1850 1860 1870 70 4,. 583 29,963 112,170 295,977 At the time of the Author's visit in October 1873 the number of inhabitants was said to exceed four hundred thousand. According to the returns of the Chicago Board of Trade, the wholesale trade of the city in dry goods, boots and shoes, clothing, groceries, iron, drugs, &c., for 1872, was K500,000,000. In the same year the receipts of cattle were six hundred and eighty-four thousand and seventy-five, and of hogs three million four hundred and eighty-eight thousand five hundred and twenty-eight, of a total value of ^75,475,000. The total receipts of lumber (timber) were 1,183,659,283 square feet (100,000,000 cubic feet), and of all kinds of grain 88,426,842 bushels. Chicago is now, in short, by far the largest market in the world for corn, timber, and pigs. Chicago is the centre of a network of railways, thirty-nine of which take their first name from the city. The word " Chicago" in the Indian language eignifleB " the place of ekunks." WATERWORKS IN THE UNITED BTATES. 51 The receipt of grain by rail alone at Chicago has reached '. « o thousand one hundred cars per day. Besides being connected by iron roads with all the harbours on the northern lakes and with every seaport of note on the Atlantic coast from the St. Lawrence to Florida, this great inland city is also in direct communication with the shores of the Pacific and with the following important stations on the banks of the Mississippi ; viz., Crow-wing, St. Paul, Prescott, Winona, Prairie du Chien, Dubuque, Savannah, Fulton, Rock Island, New Boston, Burlington, Keokuk, Quincy, Hannibal, liouisiana, Alton, St. Louis, Chester, Grand-tower, Cairo, Columbus, Hickman, Memphis, Helena, Vicksburg, and New Orleans. 10 of The City of Chicago. The city is bounded on the west by a prairie of vast extent, and was originally built on swampy ground at a level of from 3 to 4 feet only above the surface of Lake Michigan. Its 600 miles of streets and thoroughfares — many of them 100 feet wide, and lined with magnificent buildings of stone, brick, and iron, are now raised, as a rule, to 12 feet above the lake.^ When ' The raising of houses to the level of the new streets was at one time an important trade at Chicago, but it is now seldom practised. !n some cases ware- E 2 ri 52 OTHER SELECTED PAPERS. the f* fst settlers arrived, their huts were ' located ' on the banks of the River Chicago and of its north and south branches, which separate from the main stream at about 1 mile from the shores of the lake. In process of time the river — which was formerly fed by the clear waters of the lake, and therefore ebbed and flowed according to the direction of the wind — became greatly polluted, and it was determined to lessen the evil by discharging the sewage matter and other impurities of the city into the Illinois and Michigan canal, and thence into the Illinois river. This work was completed in 1871, in the manner previously described. Although there is now a constant stream from the lake up the main river and its southern branch, to the great benefit of the city, this is, unfortunately, not the case with the north branch of the river, the foul and unwholesome condition of which is daily in- creasing. The subject is now under the serious consideration of the city authorities. One remedy suggested is to obtain sufficient water from artesian wells' to cleanse the fetid creek; but it is generally considered that the best plan is that of flushing the stream by a covered canal communicating with the lake, through which river or lake water might be forced by steam power as occa- sion requires. This plan has since been adopted, and was being carried out in February 1875. The pollution of the river, not only by sewage matter, but by the refuse and garbage thrown in from distilleries, tanneries, manu- factories, and slaughter-houses, has always been a soui'ce of annoy- ance and concern to the citizens of Chicago; but in 1863 the nuisance was aggravated to such a pitch, that the water, supplied to t'. a inhabitants by pipes from the shore of the lake, became no longer drinkable. It was then that the Department of Public Works determined to supply the city with uncontaminated water froTu the lake at 2 miles from shore, in a depth of 32 feet, almost directly at right angles to the shore of the lake at the pumping works. houses of iron and stone, six stories liigli, and weighing as much as 20,000 tons, have been screwed up from 8 to 10 feet without accident. Wooden buildings have also been frequently lifted and slid along bodily from one street to another. * There are now upwards of twenty artesian wells in Chicago and its neigh- bourhood. The average yield of each was at first about 600 gallons per minute. The average depth is 1,300 feet, diameter of the bore at the bottom 4 inches, and the cost $G,000. The maximum surface-pressure of the water is 35 lbs. per square inch, which indicates a hydrostatic head of 77i feet. By the end of 1874, the wells had fallen oflf so much that some hardly flowed at all above the surface :of the ground, and the average flow had been reduced to 200 gallons per minute. ^^ WATERWORKS IN THE UNITED STATES. 53 This novel plan was designed and carried out by Mr. E. S. Chesbrough, the Chief Engineer of the city, through whose kindness the Author has been supplied with the principal part of the following information. It was found, by careful borings, that a bed of compact blue clay, at least 100 feet thick, underlay the thin crust of silt and sand at the bottom of the lake. The shaft on shore was begun in March 1864, that under the iake eighteen months later. The tunnel between them was driven from both ends. The most inte- resting work was the sinking of the lake shaft through a depth of 32 feet of water, and then through 31 feet of clay. This shaft was built, within a ' crib ' or breakwater of pentagonal form, 00 feet in diameter, 40 feet high, and with walls 25 feet thick, leaving an inner open well about 30 feet in diameter. The crib, which was constructed on shore, consisted of 50,000 cubic feet of whole timbers, 12 inches square, braced together. The inner and outer walls, as well as the flooring, were caulked at the joints ; and when the crib was towed to the intended resting-place, its fifteen watertight compartments were filled, with 6,000 cubic yards of stone to sink it to the bed of the lake. The top of the crib then stood at 5 feet above the surface of the lake. Within the well of still water a column of seven cast-iron pipes 9 feet in diameter, making a total length of 63 feet, was sunk, through the clay, to 31 feet below the bed of the lake, without resorting to atmospheric pressure, or even to pumps, though these were provided for in the contract. On the removal of the clay the tunnel was started from below. It falls 4 feet towards the shore end, where the land shf^t is 70 feet below the surface of the lake, and 77 feet below tha' ; the ground. The miners met at a quarter of the distance from the crib to the shore. The vertical axis of the tunnel, which is almost circular, is 5 feet 2 inches, and its horizontal axis 5 feet. The arching consists of two rings of brick in cement 8 inches thick. The iron column forming the lake shaft is open at the top, and has two inlet gates, the tops of which are 2 feet below low water. Through the sides of the crib are three openings controlled by gates. One is near the bottom of the crib, another midway between the surface and the bottom of the lake, and the third near the surface; so that water may be drawn from any desired depth. Chemical analysis shows that the water at the surface is slightly the purest ; in summer the water is coolest near the bottom. The tunnel can bo pumped dry at any time from the shore end by closing the inlet gates, each gate being under easy control from If r;'t 54 OTHER SELECTED PAPERS. above. The cost of the entire work, which was completed in March 18G7, was about £100,000. Since that date the duty of the pumping engines, now five in number, has been as follows : — % Average daily Greatest daily quantity pumped. quantity pumped Year ending Oallons. Gallons. 31 8t March, 1868 . . . 14.724,999 . . . 16,414,460 „ 1869 . . . 18,633,278 . . . 20,689,014 1870 . . . 21,766,260 . . . 25,712,589 1871 . . . 23,464,877 . . . 28,000,000 1872 . . . 27,536,819 . . . 31,485,000 1873 . . . 27,500,000 . . . 33,250,000 On the 9th of January, 1873, a new double-beam pumping engine, designed by Mr. D. C. Cregier, C.E., and constructed by the Knapp Ft. Foundry Company, Pittsburgh, commenced pumu- ing to relieve the other four engines, and has worked continuously since then. This pumping engine, which is said to be the largest in the United States, has two 70-inch steam cylinders with 10-feet stroke, and works two pumps of 57 inches diameter, delivering 36,000,000 gallons of water per twenty-four hours. The beams are of cast iron, 28 feet long ; their weight is 20 tons each. The main columns are 27i feet long, and weigh 17 tons each. The fly wheel is 25 feet in diameter, with a rim 12 inches broad by 20 inches deep, and the weight, including the eight spokes and ' hub ' (nave), is 33 tons. The engine was two and a half years in building, and cost K 188,400, exclusive of foundations. The combined capacity of the four engines is 75,000,000 gallons per twenty-four hours. The wattr is pumped from wells connected with the tunnel directly into the pipes. The pumping engines are guarded against the danger of this system, not merely by air chambers, but by a stand pipe, open at the top, 140 feet above the lake, supported as well as protected by a stone tower 170 feet high. The pumps are supposed to force the water to a height of 132 feet, but in the day time, when the demand is at its greatest, the water does not rise higher than the second story of the houses. During the year 1872-3 the engines consumed 13,562 tons of coal, at an average price of 28». per ton, and the cost of delivering water per million gallons amounted to 47«., as compared with 32«. and 62«. respectively for the nine years ending 1872, The water is supplied through 380 miles of mains, the largest of which has a diameter of 36 inches. Owing to the require- ments of the navigation, the pipes cannot be carried over the river and its branches (which are spanned by thirty iron and WATERWORKS IN THE UNITED STATES. 55 wood swing bridges), and therefore cross the bed of the stream. With the view of preventing damage to the pipes by anchors and by piles driven into the bed of the river, the mains are now being laid down from bank to bank in tunnels, five of which are already built. The last one was completed six months ago, between Michigan Avenue and Pine Street, whore shafts, 84 feet and 68 feet respectively, were connected by a tunnel 492 feet in length. The whole is of circular brick masonrj', the shafts being 8 feet, and the tunnel 6 feet in diameter. A 24-inch iron water pipe has since been laid through it. The cost of the work was B 13,279 (£2,600).! Before describing the new arrangements for increr.sing and insuring a sufficient supply of water to Chicago, under all eventu- alities, a few facts should be stated relative to the great fire of October 1871, by which the loss of property was greater than had ever occurred before, from an accidental cause, in the history of the world, amounting, according to the most trustworthy esti- mates, to K200,000,000 (£40,000,000). The number of people rendered homeless and destitute by this fire is calculated to have been one hundred thousand. It originated in a stable on tho west side of the river, on Sunday night, the 8th of October, 1871, in a section of the city composed almost entirely of wooden build- ings. Aided by a furious south-west wind— so strong as to blow down a church steeple — it spread in a north and east direction with wonderful rapidity, and finally terminated, at a little before midnight, on Monday, the 9th, having in one day destroyed nearly every building in its course, over a space 4 miles long and about § mile wide. It reached the pumping works early on Monday morning, when the machinery was so badly damaged that it stopped working ; thereby cutting off the supply of water, and leaving the city without the means of checking the pro- gress of the flames. By extraordinary exertions on the part of Mr. Cregier and his staff, the repairs to the engines and the buildings were so far advanced, that eight days after the fire the north engines were started afresh, and continued to supply the city without cessation for a period of two months, when the other two engines were again in working order. ' In addition to the water tunnels, the rivet is crossed by two subways in masonry for carriage and passenger traffic. These street tunnels were built with great caro and skill by Mr. Chesbrougli. The steepest gradient in the Washington Street tunnel (which was built first, and proved of immense service during tho great fire) is 1 in Iti, and in the La 8alle Street tunnel 1 in 20. The top uf the brick axching in both tuiiDels is upwards of 20 feet below the bed of the river. 56 OTHER SELECTED PAPERS. This is only a single instance, among many, of the energy with which the citizens of Chicago began to rebuild a new city on the still burning ashes of the old site. The Author found hardly a gap over the area of 1,700 acres which had been swept, only two years before, by the greatest conflagration of modern times. The rebuilding of the " burnt district " was then all but completed, and public opinion was unanimous in declaring that the Chicago of to-day is far grander than the old Chicago of 1871, before her busiest and wealthiest quarter fell a victim to the flames.' It has often been alleged that the wooden block pavement of the streets added fuel to the flames, and thus hastened the great calamity, but this was not the case. The Author has the City Engineer's authority for stating that the blocks were not burnt, and indeed that they were hardly damaged by the fire. The chief lessons taught to waterworks engineers by the fire were, Ist, to make engine-houses fireproof; 2ndly, to have as much open space round them as possible ; 3rdly, not to keep a large city dependent on one set of pumping works only, for a supply of water, especially, if, as at Chicago, there is no suitable ground on which to build a largo distributing reservoir. ' A rejident of Chicago th'is graphically described the characteristics and achievementH of the city of his adoption at the time of the Author's visit : — " It has been a distinguishing characteristic of Chicago, that all her under- takings and accomplishments were phenomenal. Her modes of action were original and sensational, both as regarded individuals and the body corporate. She took counsel of no precedents in anything she did. When she wanted to raise the grade of her streets, she elevated the city upon screws and reposed it upon higher foundations. When a supply of fresh and pure water became a necessity of our rapidly augmenting population, she carried an immense aqueduct out miles from the shore, and gathered a pellucid stream from the far-oif bosom of Lake Michigan. When the river became a receptacle of the sewage of 350,000 people, and generated an insufferable stench, she carved out a connection with the Mississippi, turned into the channel the crystal floods of the lake, and created a perennially-flowing and purifying current, sweeping away the whole accumulation of impurities, and permanently transforming a cesspool into a stream of cleanlii 'ss. And when on the woeful Sunday night of our black October, she departed partly to the skies in flame and smoke, and partly to tht earth in ashes and ruins, she maintained her plxenomenal reputation, and signalised her exit by a conflagration which outvies every one of history in all that is weirdly sublime, appallingly terrible, and amazingly destructive. Out of that broad extent of blackened desolation arose suddenly, as by the wand of enchantment, a new city, more imposing in its architecture, more colossal in its proportions, more enduring in its structures, more extraordinary in its accessories, more expansive in its enterprise, more ambitious in its projects— a phenomenon of reconstruction so preternatural, that strangers are overwhelmed with the idea that the miles of magniKcent buildings before their eyes stand on ground lately occupied by heaps of smouldering and unsightly rubbish." I !. w; WATERWORKS IN THE UNITED STATES. 57 The erection of duplicate pumflng works in another part of the city, and the construction of a second lake tunnel, to meet the constantly increasing demands for more water, were decided on before the fire. The new land tunnel, 7 feet in diameter, to connect the present waterworks with the proposed new pumping engines, will extend 4 miles westward, at a depth of 71 feet below the lake level. It is estimated that the cost of this tunnel, of the new pumping works, and of the necessary extension of mains, will be Kl,000,000, The construction of the second lake tunnel and the second lake shaft was in full progress when the Author visited them on the 25th of October, 1873, in the company of Mr. Chesbrough, the Engineer, and of Messrs. Steel and McMahon, the Contractors of the work. The excavation of the new tunnel, which is to run parallel to, and at a distance of 50 feet from, the old tunnel, is now half completed from the bottom of a hev brick shaft, 10 feet in diameter, already sunk at the shore end. The present rate of advance is 20 feet per day through compact blue clay, in which there is not a drop of water. It will be lined with bricks in three rings together 11 inches thick. The lake shaft of the new tunnel is being sunk within 9 feet only of the first shaft, in the old crib ; and, owing to this close proximity, a disturbance of the ground has taken place between the two shafts, an inconvenience which was aggravated by the plan at first fol- lowed of sinking the new iron cylinder, 8 feet in diameter and 2^ inches thick, b;;' pneumatic pressure. The prices paid to the contractors are as follows : — Main tunnel and galleries per lineal foot, including bricks 29 '50 Land sliaft „ „ 50 • 00 Lake shaft „ „ 253-00 Three gates and bulk- \ 4500*00 head at lake shaft . / The top of the lake crib above 3 water line is now being made permanent with substantial masonry. The total cost of the waterworks, including all expenses on work in progress to the Isi, of April, 1873, has been ^5,212,508, and the entire receipts during the puoi, year were ^^44,465. The money for the payment of the cost of the works has been derived principally from 6 and 7 per cent, bonds. Both the new tunnels above described — the one under the lake, 2t miles long, and the one under the land, nearly 4 miles long — were finished in 1874. Their estimated capacity for supplying water, combined with that of the first lake tunnel, is 150,000,000 U.S. gallons daily. I T ( 58 OTHBB SELECTED PAPERS. Tho following table, showing the number of United States gallons consumed by each inhabitant daily in America, as com- pared with London, Paris, and Glasgow, is abridged from a table prepared by Mr. Chesbrough. I860. 1862. 1864. 1866. { 1868. 1870. 1871. 1872. Chicago 43 44 41 43 58 73 .. 75 New York . . •• ••( 62 \ in 1867 j •• • • 85 •• Brooklyn . 17 26 33 43 47 46 • • Jersey City. . ■• •• \inl865/ •• 84 •• 99 Pliiliulclpliia . , , ,. 51 55 55 54 Washington , , , , , , 134 Boston , ,, 55 62 60 54 ^ , Albany . , . ., 80 Detroit . 58 57 60 67 64 73 83 Buffalo . . . • • , , 51 61 Cincinnati . . 39 , , , ^ • • , , 60 Montreal . ^^ , , .. • • 55 , , London. . . ••{ 38 \ in 1867/ •• • • Paris , , 29 , , , , , , Glasgow . . • • 60 61 •• Mr. Chesbrough remarks, that the past rate of consumption in London and Paris is very small as compared with that of most American cities, and that only Glasgow is supplied after tho American fashion. He is of opinion that the fairest comparison of the water supply of diflferent cities would be by showing the quantity furnished to each water-taker, instead of supposing it to be used by the entire population ; and ho is fully aware that the enormous demand for water in some cities i^ to be attributed largely to leakage in the mains and distributing pipes. I IV.— LAKE HARBOURS. The lake harbours, of national importance in the United States, are designed by, and constructed under the superintendence of, the Engineer officers of the Army ;^ and in Canada by Civil Engineers in the employment of the Government. With hardly pn exception, the protecting works and quays consist of timber boxes, or cribs, iilled with stones, and joined to each other, ' This distinguished corps consists of one hundred and six officers, the ma- jority of whom are engaged on public vorka and eiureys, and the minority on fortifications. LAKE HARBOURS IN THE UNITED STATES. 59 after they have finally settled down, by a continxious timber supor- Btructuro carried up a few feet above the level of the water. By this simple expedient, breakwaters, piers at the mouths of rivers, and wharves, have been erected within the last fifty years, at a comparatively small cost, at the most important points along the shores of the great chain of inland lakes, as well as at most of the river harbours communicating with the Atlantic ; and experience has hitherto proved, that no cheaper and better system could have been devised for providing efiicient harbour accommodation, in loca- lities where timber and stone abound, and where every workman is skilled in the use of axe, hammer, and saw — the only tools required in putting cribwoik together. It is superfluous to add that American engineers are well aware that, in building provisional works of this description, the expense of maintenance is much greater that if, in the first instance, the work had consisted of durable materials only, and that therefore it often costs more in the end. They per- fectly understand that the advantage gained in the meantime by the construction of a cheap and simple work, which can readily be made permanent when required, far outweighs the element of ulti- mate economy in the abstract, in a young country where an imme- diate and strictly economical use of the slender means at the disposal of the inhabitants, to attain the end in view, is a necessity. In consideration of the above circumstances, and on the assumption that a full description of the most approved style of cribwork now built in America will be read with interest by English engineers employed abroad, the Author would draw their special attention to the specifications in the Appendices II. and III., which embody the results of the best experience in this class of work up to the present time ; and to the remarks which follow on the same question. As the lake harbours greatly resemble each other, the Author's " Notes " need only be given here concerning the two principal lake ports, viz., Chicago and Buffalo, which, moreover, offer the best types of harbour works in general on the shores of what may justly be termed the great inland seas of North America. Port of Chicago. — The great importance of this harbour, which has not yet been in existence half a century, is strikingly evi- denced by the following statistics, of the Chicago custom-house authorities, for the year ending the 30th of June, 1873 : — No. Tonnage. Vessels arrived . . . 12,394 • • 3,062,979 Vessels cleared . . . . 12,324 • • 3,142,169 Totals . . 24.718 6,205,148 * • 60 OTHER SELECTED PAPERS. ■ ' BUVENUE CULLEGTEU. $ Duties on imports 2,150,1G0 ' • ' Marine Hospital moneys 7,859 •• Tonnage dues 8 , 530 Steambout inspector fees 6,2'.)3 Fines CG5 ' ■ -• ■ ■ -= ' • > ^.- Total . . . 2,173.507 From tho establislimont of Chicago as a port, when there was only a depth of 2 or 3 feet of water on the bar at the mouth of the river, to the end of the year 18«?5, tho town spent large sums of money in keeping the mouth open by constant dredging, and by frequent extensions of the piers, to keep pace with tho growth of the land. From 1821 to 1866, the coast line immediately to the north of the north pier advanced 2,400 feet into tho lake, or at the rate of 56 feet per year. " There is a shingly shore north of Chicago, and hence largo annual accretions behind the north pier. The Chicago river is not muddy." ^ In the autumn of 1865, General T. J. Cram, U.S.A., recommended a further prolongation of the north pier for 600 feet beyond the extension made by the city of Chicago in 1864 and 1865, and the rebuilding of the old south pier, and its extension for a length of 610 feet. In August, 1866, Colonel Wheeler, U.S.A., then in charge of the works, reported as follows : — " The accretion of tho sand on the north side of the pier goes on rapidly, and there appears no better way of counteracting its destructive influence on the channel than to extend the north pier. I see no reason for building the south pier. The object of parallel piers is to confine the volume of water pouring out of a river, and to make use of tho current to scour out and maintain a channel. There is no use in attempting this plan with the Chicago river ; for I may say there is no perceptible current in that river. We are limited, then, at present to the prolongation of the north pier, and to removing any bars that may form in the channel by dredging." In pursuance of this opinion, the extension of the north pier for a length of 608 feet was let to a contractor, in the au+amn of 1866, for the sum of K86,874. The work was to consist of nineteen cribs, each 32 feet long, 30 feet wide, and 28 feet high, the depth of water in which they were to bo built varying from 17 to 23 feet. The contents of the entire work amounted to 18,295 cubic yards. On this basis the accepted tender was at the rate of J8143 per lineal General Humphreys, Ex. Doc. No. 220. 43d Gocgrcss. LAKE HARBOURS IN THE UNITED STATES. 61 foot, or K^i (18«,) por ciihic yard.* Before the extension was com- menced in 1807, the Chicago Canal and Dock Company suhniitted a project, which was approved by the Secretary of War, for an entrance to their basin at the end of the pier. In his annual report of 1867, the officer in charge recommended a reduction of the length of the new pier to 300 feet, as that would carry the extremity of the extension to the point originally proposed; but sufficient materials having been collected to build 400 feet of pier, it was thought best to use them to complete that length. In October, 1869, General Humphreys reported that the building of the south pier, and its extension as far as the Lighthouse Pier, a distance of 610 feet, had been contracted for, and that the greater portion would be executed by the end of the season. Ho at the same time recommended that it should bo carried on until it was equal to the north pier. By October 1870 the south pier had an exten- sion of 1,224 feet, except the superstructure, which was then only built on the 614 feet of cribwork sUnk in the previous year. On the 11th of July, 1870, an Act was passed for the enlargement of harbour facilities, and for a harbour of refuge at Chicago, according to plans submitted from the office of the Chief of Engineers. On this account the work on the south pier was suspended. The Act takes into account the construction of a commercial harliour, designed by Colonel Wheeler, as follows : — " My plan is to inclose a portion of the lake, forming an outer harbour that would meet the present wants, and capable of being enlarged as the future might require. The extension of the sotith pier should bo continued until it is equal in length to the north, then build a breakwater at right angles, and extending southward for 4,000 feet, and then join this breakwater to the shore by a pier. An opening of 300 feet or more to be left in the pier forming the north side of the basin, to admit vessels from the harbour entrance. This basin would contain an area of about 275 acres, one-third of which would have a depth of over 12 feet of water, and the re- mainder of over 7 feet, that can be easily deepened to 12 feet, affording a splendid harbour of refuge for all classes of vessels sailing to and from this port at the present time. To make this basin would require, besides the extension of the south pier, already estimated for, the construction of 4,000 feet of breakwater for the eastern side, and 3,460 feet for the southern side. The eastern • The cost of tho concrete blocks, now employed at New York for the new quays, composed of 1 of English cement to 7 of broken stone or gravel, is 48«. per cubic yard. 62 OTHER SELECTED PAPEI18. If ' eido should connist of cribs not less than 30 feot wido, 50 foot long, and at least 8 feet above the surface of the water. This would require them to bo 30 feet high. The southern side, for the first half from shore, should be made of cribs 20 feot wide, 32 feet long, and 17 feot high ; the remaining half of cribs 25 feet wide, 60 feet long, and not less than 5 feot above the surface of the water, or 24 feet high on an average. " Coat of tbo breakwater at $150 per lineal foot , „ shoro end of the pier, 1,7G0 foot, at $.'55 . ,. ' outer half of the pier, 1,700 feet, at $99 . „ dredging say '' " Total . . . = per cubic yard. $ 4-43 4-40 $ 600,000' 90,800 108,300 ■ 34,900 900.000" Colonel Wheeler's plan was duly approved by the Department of Public Works, and during the fiscal year ending the 30th of Juno, 1871, twenty -nine cribs, 50 by 30 feet, were sunk, making 1,450 feet of breakwater, including 300 feot at its north end running west. The first crib was placed in 24 feet of water, and none in less than 18 feet. By the 30th of June, 1872, 2,250 feet of breakwater had been constructed at a total cost of ^200,000, or K8B-88 per running foot, and it was then estimated that the whole work would not cost more than ^100 per foot, including covering and contingencies. In November, 1871, Colonel D. C. Houston, who then, and at the time of the Author's visit, had charge of the harbour works at Chicago and other ports in Lake Michigan, submitted a modified cross section for the breakwater for the approval of the Chief of Engineers.^ Colonel Houston gave the following reason for the proposed modification : — " In nearly all the harbours under my charge the natural bed for cribs is sand, and it is found that even in the greatest depth of water, when cribs have been sunk (as at Marquette, in 28 feet of water), the sand moves during storms, causing the cribs to settle unevenly, to tilt outwardly (toward the exposed side), and, in some instances, to shift their position. It is indeed, a rare case that a crib maintains the exact position in which it was at first placed. The grillage bottom, which allows » A detailed estimate of the cost of one of the cribs for this work will be found in Appendix IV., and its mode of construction is shown in the isometrical sketch of a crib 50 x 30 x 27i feet (Appendix II.). ' Col. Houston kindly presented the Author with various designs for cribwork and with upwards of forty plans of harbours in lakes Superior, Huron, Michigan, Erie, and Ontario, where jetties have either been recently carried out or are in progress. LAKE HARBOURS IN THE UNITED STATES. 63 a portion of the stono to work through tho Band, is a very partial roniody for these ovils. Tho dovico of placing aprons of loose stone on tho outside of the cribs has boon resorted to with great benefit, but it is not satisfactory, and in many cases a storm comes up and shifts tho crib by the undermining process before the riprapping can be put in." . . . " It has boon my object to devise some economical plan of foundation for cribs on such bottoms to prevent this universal displacement." . . . "In the actual construction of piers during tho past season, tho oflBcaoy of ' stono foundations ' for cribs has been incidentally demonstrated." Colonel Houston therefore recommended the employment of rubble stono foundations for crib work at Chicago, and stated his opinion that, at that place, stones would rest undisturbed by the waves at a less depth than 10 feet in the most exposed situations. After some correspondence. Colonel Houston's proposal was agreed to, and carried out with the best results.^ During the year ending the 30th of June, 1873, the east break- water was extended 800 feet by the Illinois Central Eailroad Company, and up to tho same date a length of 3,050 feet had been constructed, including the return at the north end. It was then estimated, that, during the following year, an additional length of 1,100 feet would bo added, leaving only 150 feet of this work to be completed according to tho original design. In the annual report on the works for 1873, it was stated by Captain Hinman, U.S.A., that the following method of building a foundation for a crib had been adopted, and had answered admirably. " As soon as the crib is in position, it is loaded with stone until it settles to within about 4 feet of the bottom of the lake. Fine rock is then thrown in, which, passing through the grillage bottom, settles evenly under and around the sides and ends of tho crib ; the latter is then filled up with coarse stone and riprapped with about ten cords of heavy rock. In order to hasten the building of a foundation, it is suggested that a portion of the fine rock be put in through a dump-scow just before the crib is brought up ; in this case coarse rock would be used." With reference to the south breakwater, it is now a question whether it should be constructed or not ; for if the east break- water is to be extended beyond the length originally proposed, the ' In corroboration of Col. Houston's views regarding the utility and economy of rubble foundations for cribwork on a yielding bottom, tbe Author has given a short account, at the end of these Notes, of his own experience of cribwork on the shore of the Black Bea. 64 OTFTSB SELECTED PAPERS. former would not only be unnecessary, but injurious to the harbour. According to Colonel Houston, the decision of the question depends upon whether the lake front is to bo used for dock purposes or not. If not, then the basin will, as it is designed, meet all the require- ments of a roadstead for many years to come. In case, however, of the construction of wharves and of the transfer of business to the lake front, an extension of the east breakwater will be a necessity. As regards further extensions of the north pier, Mr. E. S. Little- field, U.S.E., foreman in charge of the work, " whose experience and observations entitle his opinion to consideration," reported as fol- lows, in April, 1873 : — " The works on both sides of the entrance to tht iver are out an equal distance into the lake, and during N., N.E. and N.W. blows a heavy sea rolls in along the return, and into the entrance to the harbour-basin formed by the breakwater, making it difficult, and at such times dangerous, to take out stone and other materials to the works.". . ." Canal-boat men would not take the risk of towing across the opening between the south pier, and the return, with any sea on outside. At such times, too, the sea sitrikes the return, and is deflected across and into the slip at the north pier, making difficult navigation from E. of the lighthouse, espec ially where the water ie 14 feet depth and less, as loaded vessels are likely to strike.". . . " Adding to the return would not prevent the rough sea between the north pier and it, and only partially give protection to the entrance into the basin or harbour, while it would injure ma- terially by narrowing the entranc ). Lengthening the north pier 400 or 500 feet would aiford all the safety needed to docks inside the basin, and would save the present width between the return and end of south pier, and make it comparatively easy for vessels from outside to sail into the outer harbour or basin. Likely it is only a question of time that the north pier will be extended, and not at greater cost now than at some future time. If done at present the breakwater can be extended with greater economy afterwards." The above opinion is confirmed by the experience of Colonel Houston, and he has therefore included the cost of extending the north pier 400 feet in his estimates for 1873-74. Buffalo Hakbour is situated at the north-east xngle of Lake Erie, and is therefore greatly exposed to the violence of south-west winds, in which direction the lake has a ' fetch ' of 200 miles. Thus more than ordinary care is needed, to provide safe harbour accom- modation, for the large fleets of vessels constantly arriving at LAKE n VqI;XL. SMiitm 1674-7B Part 8. THOI BTr.T,,Ijni. LOUDON PLAN SHOWING THt NAVIGABLE ROUTIS BCTWECN THE LAKES AND THE SEABOARD, CBA? A. KAHTLEY, DEL? J OJ limb nil Minute 3 of Prooeot un^ (£ Tha BiBlilutian uf Civfl. En^ixe LAKES AND THE SEABOARD, AND THE COURSE OF THE UPPER MISSISSIPPI AND THE OHIO RIVERS. VIMT K « . fThofiiBlihjtiaftoi' Cnril Eii#x\i«ir»,VQL2L. Seneicm 1874_7f .Btrt. 2. hmmmt THOIKEUj.UTH. 4,0311 l Bf POTENT dAMlBN. y IM.ATF. 7. S J S s J P ^ ^ itU Jl S £.. Ji^Milt, Uf 'isril E.u^iB«MS, VqIiZL. Session 1874-7B, Part 8. THOl JJEIX.Xira. LONDON. m 3S3Q;5S!1P1F3 SSfl (D 13 "ir OH 3 . IM.ATF. 7, o SOUTH UOXl^>i|!* V 3tf 24 72 JTB. Thr Smm'iinrf.' nve in t'fH ■ ^sissiP 9 I ■'( 3 f- i- 7 1 t. -J 1_ I tsjfilej «' CHAS A.HARrLT=;T, JIKLT Mimttes at Proneeain|3 cf Hue Tnatatntixm rf dnal EngiueeiB. VoI:XL, Sssaion 1874.-75. Part S, THO! KEEL.ilTH.. LONDON